All plants grow toward sunlight, except when then don’t.

In nearly all cases, plant stems, vines, and bines grow upward, reaching for the sun’s energy. Plants deprived of sunlight will often grow longer than they can support, in an effort to reach that energy source. This is called etiolation. But, sometimes, it is better for a plant to grow away from sunlight. This behavior is called skototropism.

The dark side

Light levels are pretty dim at ground level in a thick jungle. If a vine does not find a tree to climb, it will die. If it heads toward visible light (an opening in the canopy), it will never find a tree to climb. Instead, these vines must grow toward the darkest place they can find (the base of a large tree) in order to find something big enough, strong enough, and tall enough, to provide support. What’s really interesting, is that larger trees attract more vines, while smaller trees attract less vines. There are even mathematical formulas that describe skototropism among certain jungle seedlings!

Once a climbing plant has found a support structure, the skototropism behavior is turned off and upward growth (phototropism) begins in earnest.

[Some scientists believe that roots grow down because of skototropism, while others believe it is something called gravitropism. You decide.]

Traveling in Germany a few years ago, I was a little confused by grids of 20-foot poles pointing skyward. They looked alien, like a giant, bristling growth. That was before I learned about hops.

Hops are flowers from the Humulus lupulus plant and they love to grow up!

Hops in beer

I do not know how to make beer, so my knowledge in this area is limited. [Brewers, feel free to add better information in the Comments!] I do know that hops have been used in beer-making since the 9th century. Before that, other flowers and bitter herbs were used, including dandelion, marigold, horehound, and burdock root, in a mash called gruit. One of the main reason brewers switched to using hops was because there was a tax on gruit, but no tax on hops. Of course, that situation was only temporary. Hops are said to have an antibacterial effect, as well as providing a bitterness that balances malt’s sweetness. It is the unfertilized female flowers that are used in beer-making. The acids in beer have sedative properties, with or without alcohol.

Hops varieties

The flavor and aroma of hops flowers is largely the result of where they are grown. While there are many different hops cultivars, the plants can be [overly] simplified into three different types: American, British, and Continental European. American hops are robust, heavy producers with long sidearms. They tolerate a wider range of soil pH and soil structures. American hops are generally planted 4 feet apart in rows that are 14 feet apart. Common American varieties include Willamette, Chinook, Brewers Gold, and Zeus. British and Continental European varieties are genetically different from the American varieties. They have smaller, finer root systems and are less tolerant of soil variations. These varieties have shorter sidearms and can be grown 3 feet apart in 12-foot rows. This allows for more plant density on the same acreage. British varieties prefer more alkaline soil (pH 6.5 or higher) and can tolerate heavier soils. Common British varieties include Viking, Fuggie, and Challenger. Continental European varieties, such as Magnum, Glacier, and Pearle, prefer more acidic soil (pH 5.5 to 6.2). One subset of the European hops, referred to as noble hops, are less bitter, with a stronger aroma than others. These hops are used to make Pilsners and other mild beers.

Hops plant structure

Hops flowers are green, soft-petalled seed cones, also known as strobiles. Hops plants are dioecious, which means the plants are either male or female. To prevent male pollen from fertilizing the female flowers, plants are propagated vegetatively. When hops plants are grown from seed, the males are culled as soon as they are seen, similar to other flower bud crops. The hops vine is called a bine. As the bine wraps around a support, side branches, called sidearms, emerge. At the end of the growing season, everything aboveground dies back. In spring, the roots put out new bines and the whole process begins again.

How hops grow

Hops plants are fast growing, perennial climbers. That’s what all those poles and strings were - hopfields or hop yards. Hops grow from rhizomes that are placed in ‘hills’ or mounds that are 6 to 12 inches high. This helps with drainage. The rhizomes are placed 4 inches below the soil surface. Commercially produced hops are generally started in pots, in March. Then they grow in greenhouses until July. Plants are placed 7 to 8 feet apart in a grid formation that matches a series of poles that support strings used by the hops plants to climb toward the sun. In these commercial fields, air flow is critical to disease and pest management, so the bottom 3 feet of foliage is removed. If you are growing just a few plants for yourself, you don’t need to do that.

One way plants store food and reproduce is with a structure called a corm.

Reindeer love it and your trees may wear it, but what is lichen?

Lichen is primitive and complex, but it is not a plant. Nor is it a fungi. Well, not exactly.

Lichens are one of Earth’s more bizarre life forms. You know it when you see it, but that’s usually as far as it goes. Before we learn the secrets of lichens, let’s review some basic plant and fungi facts that will help us understand lichens better.

Plants and fungi

Some 500 million years ago, when life was sorting itself out here on planet Earth, tiny bacteria, called cyanobacteria, learned how to absorb the sun’s light energy and convert it into food. These talented bacteria were swallowed up by primitive plant cells and later evolved into chloroplasts. Chloroplasts are the organelles within plants where photosynthesis occurs.

    Fungi - Fungi are not plants. They are their own kingdom and they do not have chloroplasts, which means that they cannot produce chlorophyll or perform photosynthesis. Fungi get all their nutrients from decomposing organic material.

    Algae - Algae are also not plants. And they, too, have their own kingdom (Protista). Algae (or alga, if you only have one) come in many different colors. Algae contain chlorophyl but they do not have leaves, roots, true stems, or vascular tissue.

    Bacteria - Bacteria are one-celled microorganisms that lack a nucleus. [Did you know that a single teaspoon of soil can contain up to one billion bacteria?] Most bacteria are parasitic decomposers. Many are beneficial. In fact, we could’t digest our food without the help of bacteria in our gut.

    Lichens - Lichens are not plants and they do not have roots, stems, or leaves. If you cut a lichen in half, you will often see distinct layers. It’s what makes up these layers that make lichens so strange.

What are lichens?
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Lichens are actually two separate organisms living in a symbiotic relationship. A lichen is a fungi combined with either algae or those cyanobacteria mentioned earlier. The fungi is the boss and it dictates the way a lichen functions and grows. The algae and the cyanobacteria perform photosynthesis, providing the combined unit with food. This means that the lichens on your tree are generally not causing any harm. Heavy lichen growths can interfere with light and gas exchanges. Lichens retain moisture and can survive complete dehydration.

Parts of a lichen

While not obvious to the naked eye, lichens have distinct parts:

• thallus - the vegetative body, not including reproductive parts 
• cortex - hardened outer layer, usually brown, orange, or yellow
• photobiont layer - algal or cyanobacterial layer where photosynthesis occurs, is brightest green when moist
• medulla - fuzzy white layer, mostly fungal vegetative material (hyphae)
• rhizine - small hairs used to attach lichen to surfaces

Types of lichen

There are several different types of lichen, based on their growth behavior:

• crustose (crusty, above) - thin red, yellow, orange, gray, or green layer is held tightly to a substrate
• foliose (leafy) - leaf- or strap-shaped lichens with distinctly different upper and lower surfaces
• fruticose (shrubby) - three-dimensional lichen may look like a shrub or a pedestal, or they may feature dangling threads
• gelatinous - without internal structure
• leprose (dusty) - this lichen grows in a fine coating that looks like dust
• squamulose (flakey) - clusters of tiny ‘foliose’

Lichen reproduction

Lichens reproduce both vegetatively and sexually. Vegetative reproduction can be as simple as breaking off a piece of an existing lichen. All of its natural processes will continue. Bacteria reproduce through cell division (mitosis). The fungal portion of lichen can produce fruiting bodies that release spores which take to the wind and land elsewhere. These spores must mature and connect with suitable bacteria to become a lichen. Since there are several different types of fungi that can become a lichen, the individual structures may vary.

Does ‘decurrent’ mean that your fruit and nut trees have gone out of fashion?

No, that would be démodé and left entirely to personal opinion. Decurrent may refer to a tree's (or a leaf’s) overall growing behavior, or it may mean you have some pruning to do.

Decurrent trees

​Trees are described as either decurrent or excurrent. Excurrent trees have a single trunk all the way to the top. Pines and most other gymnosperms are examples of excurrent trees. Most shrubs and angiosperm trees are decurrent. Decurrent trees get most of their structure from scaffold branches. Scaffold branches are lateral (side) branches that are no more than half the diameter of the main trunk (less than one-third is even better). Most fruit and nut trees are decurrent. The decurrent growth is caused by weak apical dominance. Apical dominance simply means that the main central stem grows faster than everything else.

Decurrent leaves

Some leaf blades wrap themselves around a length of stem. These are decurrent leaves. The grass in your lawn is decurrent, as is mullein. The gills of a mushroom are also described as decurrent because the gills of many varieties are attached downward on the stem.

Pruning decurrent trees

Decurrent trees should be pruned in such a way that the main trunk is kept to approximately two-thirds of the tree’s overall height. The trunk, or central leader, should not be topped or headed back unless necessary to control for size. Secondary trunks are removed and the overall structure of the tree is developed with scaffold branches. Decurrent trees with multiple trunks are more prone to storm damage, but they tend to grow that way naturally. These extra trunks should be removed.

​Decurrent branches

Branches that grow upward get more sun and tend to be mostly vegetation (leaves). Branches that are predominantly horizontal produce the most fruit. Decurrent branches, the ones growing from the bottom of supporting branches, tend to lose vigor and generally only produce small fruit. This is not the same thing as a heavily laden branch being pulled downward by the weight of its harvest. Decurrent branches should be removed as soon as they are seen, taking care to not damage the branch collar. Decurrent branches can also increase the chances of torn limbs, if the crop is particularly heavy. Removing these downward facing branches will redirect your tree’s efforts toward the more productive branches.

​Decurrent is not the same thing as those squash plants that someone forgot water last August. That’s wilting. Decurrent is a growing behavior, not a dying behavior.

Cardoons (Cynara cardunculus) are edible thistles from the sunflower family.

​Eaten the same way as celery, or cooked into stews and soups, cardoons are a maintenance-free perennial. The familiar, grocery store variety of artichoke is a type of cardoon, but there are differences.

Native to the dry climate of Morocco, cardoons are unfazed by drought, making them an easy choice in California and other Mediterranean climates. Also known as artichoke thistles, cardoons produce magnificent pinkish-purple spiked flowers from April through July, but it is the stems that are eaten.

Cardoon description

Wild cardoons are sturdy herbaceous perennials that grow 3 to 5 feet tall, with deeply lobed, greenish-gray leaves that can be spiny, hairy, or downy (a condition called tomentose). The fleshy taproot is very good at finding water. And pollinators love the big, showy flowers!

Cardoon types

Cardoons are grown for two different crops, using different cultivars. The familiar globe artichoke (Cynara cardunculus var. scolymus) is grown for its large edible flower buds. The plant referred to as ‘cardoon’ (C. cardunculus var. altilis) is grown, instead, for its edible leaf stems. Since the wild ancestor to cardoons featured painful spines on those stems, spineless cultivars have been developed. Our domesticated artichokes and cardoons are so closely related that they can cross-pollinate, so they should be grown a fair distance from one another.

How cardoons grow

Cardoons need a long, cool growing season, making them an excellent winter crop in the Bay Area. Seeds are started late fall to mid-winter and they transplant easily. These plants grow slowly, at first, but don’t let them fool you. Cardoons can get quite large, averaging 3 feet in all directions. Plants need full sunlight, moderate amounts of water, and good drainage. Watering regularly improves the flavor of cardoon stems. They are frost sensitive, so some protection may be needed in the form of mounded straw or dry leaves around the base of the plant during winter. The plants often die back to ground level after flowering, but they will come back, year after year, adding structure and color in winter, and a spectacular show in spring and early summer.

Harvesting cardoons

Only the tender, inner stalks are eaten. These are harvested before the plant goes to flower. Much like celery, these stalks are wrapped in fabric, paper, or straw during the 30 days of growth. This etiolation, or bleaching, keeps the stems white and tender. Traditionally, the stalks were buried under a mound of soil as the plant grew, but that just sounds like too much work. The stalks are then peeled and treated with a little lemon juice, to prevent browning. Simmer for 30 minutes or so and add to any number of Moroccan, African, Greek, Italian, or Persian dishes. In addition, cardoon seeds contain a high quality oil, similar to sunflower oil and safflower oil.

Cardoon pests and diseases

Like its close cousin, the artichoke, cardoons are vulnerable to feeding by slugs and snails, and the artichoke plume moth. They are also susceptible to the viral disease artichoke curly dwarf. Other than that, they are relatively indestructible.

An invasive weed

Cardoons are so hardy, and they self-seed so readily, that they are categorized as a Most Invasive Wildland Pest Plant by the Invasive Species Compendium. What this means to you, as a home gardener, is that it is very important that mature flowers are deadheaded before seeds can spread. This will protect the environment and prevent your yard from filling up with pokey thistle plants. Cardoons grow and spread so readily that some researchers are studying them as a source of biofuel and bioplastics materials.

Invasive weed or delicious vegetable, cardoons have been part of the human diet since ancient times, only falling out of public favor over the last 100 years.

As easy as it is to grow, perhaps it is time for a cardoon in your foodscape!

Types of cambium

There are two different types of cambium. They are cork cambium and vascular cambium.

    Cork cambium produces new bark on its outer edge and it has a layer of cells containing chlorophyll on its inner surface. If you scrape the outer bark off of a twig, you can usually see a green area under the bark. This is the cork cambium layer. Potato skins are another example of cork cambium tissue. If you are ever lost in the woods and hungry, you can eat the cambium layer of most pines, slippery elm, black birch, yellow birch, red spruce, black spruce, balsam fir, and tamarack trees. [I have no idea how it tastes. At that point, you probably won’t care.] 

          Vascular cambium is where most of the width of dicots and gymnosperms is produced. [Most monocots lack secondary growth.] Vascular cambium is found between the phloem and the xylem. Vascular cambium produces xylem tissue on its inner surface and phloem tissue on the outer surface. You can see the vascular cambium in herbaceous plants as beads on a necklace when a cross-section is taken.

Cambium through the seasons

In spring, when water is more abundant, the ring produced by the vascular cambium is usually wide and light colored, while the portion of that ring produced later in the summer is usually darker and thinner. These two rings together represent one year of growth. The cambium layer is relatively inactive during cold periods, which is why plants don’t do as much growing in winter. Many gardeners take advantage of this fact when grafting new scions onto existing trees and other plants. It is the cambium layers of both plants that must connect for a graft to be successful.

Damage to the cambium

If the cambium layer is killed by fire, freezing, pests, or disease, the plant will die. Many animal pests are attracted to the moisture found in the cambium layer. Gophers, ground squirrels, voles, deer, horses, and rabbits will gnaw through the outer bark, especially during severe drought. This activity can girdle a tree, killing it. Deliberate girdling (removal of the outer bark around the circumference of a tree) is used to increase fruit yield, size, and quality, but care must be taken to not damage the cambium layer. Tree supports, left on for too long or tied too tightly can also damage the cambium layer, killing the tree.

Many insect pests will burrow their way into the cambium layer, using it as food, breeding grounds, and protection. Very often, these insects can kill a mature tree. They include bark beetles, American plum, shot hole, Pacific flathead and other borers. If that weren’t enough, freezing temperatures and fungal cankers, such as phytophthora, armillaria, crown gall, and crown rot, can also kill the cambium layer.

Sapsuckers are a type of woodpecker that drill a series of holes in the bark and cambium of trees to get at the sap and the insects attracted to the sap. 

Who (or what) is attacking your plants' cambium layers?

How do cuttings work?
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Being able to produce a new plant from a piece that was cut off is due to two conditions called totiopotency and dedifferentiation. Dedifferentiation means a specialized cell can return to a state of undifferentiated, meristem tissue, which can then become any other cell found within that plant. Totiopotency, or cell potency, means that every cell contains all of the genetic information needed to generate the entire plant, much like the supreme personage of Element Five movie fame. This means that, in theory, a single cell can be used to regenerate a new, identical plant. Of course, outside of the lab, your chances of success are much higher if you have many, many cells to work with. Let’s see how the different methods of cuttings can be used to propagate your plants.

Leaf cuttings

The Jade plant mentioned above is an example of a leaf cutting. In that case, new roots, and then new stems, are formed at the wound site, after it has had a chance to dry a little. Most plants cannot be generated from leaf cuttings. While a few spindly roots may appear, they quickly rot and die. Leaf cuttings are best suited to succulents, cacti, and a handful of popular tropical houseplants. These plants can form new roots at the base of the petiole, or leaf stem, from the axillary (or lateral) bud, or from the leaf veins. There are four types of leaf cutting:

• leaf sections - cut a leaf into wedges or sections, making sure that each wedge has a vein; lay each segment on the medium (woody begonia) or insert the bottom leaf edge into the medium (snake plant)
• split vein - cut into the veins on the underside of a leaf and lay it, cut side down, on the medium; you may need to weigh the leaf down, if it starts to curl (Rex begonia)
• whole leaf with petiole - remove the petiole along with the leaf and put the end of the petiole in the medium; once new roots have formed, the leaf can be removed (African violet)
• whole leaf without petiole - this method is for sessile leaves (those without a stalk or petiole); place the cut end of the leaf in the medium; the leaf may be removed once roots have formed (Jade, donkey’s tail)

​Stem cuttings

There are three basic types of stem cuttings: herbaceous, softwood, and hardwood. Brand new growth is “green” or herbaceous, softwood is slightly more mature, and hardwood is woody and fully mature. [This is not the same thing as hardwood and softwood trees.] Hardwood is the most difficult to propagate with cuttings. Some plants, such as mint, seem to spread whether you want them to or not. Very often, these plants are well-suited to propagation by stem cuttings.

​      Herbaceous stem cuttings are taken in spring. Make sure that your stem cutting contains both nodes (where leaves and buds occur) and internodes (the spaces between nodes), since some plants generate roots at one, while others root at the other. If you have both, it won’t matter. Tomatoes, basil, sage, and many other herbaceous plants can be propagated this way.

     Hardwood cuttings are taken from fig, grapes, pomegranates, quince, blueberries, mulberries, some plum varieties, currants, kiwifruit, and gooseberries, while they are dormant. There are three types of hardwood cutting: straight, heeled, and mallet. Straight hardwood cuttings are simply 6 to 15 inch segments cut from near the end of pencil-width, one-year old branches, using a flat cut, removing any unripened green growth from the terminal end using an angled cut. [There is not enough food in the growing tip to be useful.]

​At the proximal, flat-cut end, remove some of the outer bark, exposing a little of the cambium layer (light green). If you are using rooting powder, do so at this time by dipping the exposed area in the powder, tapping the branch gently to knock off the excess, and then insert the stem in a hole created with a dibber (or a pencil). This prevents the rooting powder from being scraped off. The stem should be submerged in the rooting medium, leaving only the top bud above soil level. Mallet and heel cuts are used for the most difficult to propagate plants. Heel cuts include a portion of the parent branch, while mallet cuts include small segments from the parent branch.

​     Softwood cuttings are more likely to succeed when taken in mid-summer. Softwood plants include perennials, such as blueberries, rosemary, thyme, sage, oregano, lavender, lemon balm, as well as some ground covers, vines, shrubs and trees.

You know how amazing it is that roots always know to go down and stems tend to go up? Well, when you take a stem cutting, the bud that was closest the parent plant’s center (proximal end) will become the roots, while the end that was farthest away (distal end) will become stem tissue. This is due to a behavior called polarity, caused by auxins within the stem. (Auxins are plant hormones.) Simply turning them upside down does not change this behavior, so plant accordingly. Also, because buds contain the auxins needed to stimulate root and stem growth, make sure there are buds on your stem cuttings, and that the area around the bud is not damaged. If there are any leaves present, let them stay, as long as they are not too big. Leaves are a source of auxins and other cofactors used to stimulate root development, as well as food through photosynthesis. If the leaves are too large, they can be trimmed down with a pair of scissors.

Root cuttings

Many people mistake the spreading habit of plants produced by stolons and rhizomes as a form of propagation by cuttings, but this is not accurate. Those plants produce roots and stems at broken points as a natural growth behavior. Root cuttings, on the other hand, produce new stems and roots at the pericycle, which is the area between the epidermis and the phloem, near the cambium layer. Adventitious roots are more likely to occur when root cuttings are taken from juvenile plants than from older plants. Plants propagated from root cuttings may exhibit new characteristics (phenotype) due to normal genetic behaviors of different layers of cells (periclinal chimera). In English, this means that root cuttings taken from a thornless blackberry will produce blackberry bushes with thorns.

    Large rooted plants - Root cuttings are generally take from 2 and 3 year old plants during the dormant season. To help you remember which end of the root is the top, make the upper cut horizontal, while the lower cut is angled. You will need a segment that is 2 to 6 inches long. Store your root cutting in moist peat moss, sand, or sawdust at 40°F for 3 weeks. Then, insert the entire root cutting into the medium, with the flat, top edge level with the rooting medium. (horseradish)

    Small rooted plants - You will only need 1 or 2 inch sections of these roots for cuttings. Then, simply lay them on the rooting medium, about 1/2 an inch deep. (geranium, bleeding heart ming aralia)    

Rooting factors

Plants are classified according to their rooting ability: rapid rooting, auxin-requiring, or cofactor-deficient. Rapid rooting plants have everything they need and will begin rooting right away. Auxin-requiring plants need help from a root compound that contains, you guessed it, auxins. Some plants contain root inhibitors and they lack the rooting cofactors. Simply applying rooting hormone will not help.These plants are really tough to grow from cuttings.

Success factors

There are many factors that have an impact on whether or not your cuttings will survive and thrive. These factors include environmental conditions, the physiological state of the plant cutting, and the rooting media or soil.

• Environmental conditions include temperature, moisture levels, light intensity and duration, and oxygen levels. If it is too hot or cold, too bright, too wet or too dry, the cutting is less likely to survive. Temperatures of 70 to 75°F are ideal.
• Physiological status includes overall health at the time the cutting was taken, including carbohydrate and nutrient levels, and whether or not girdling or etiolation have occurred.
• Rooting media or soil must be loose enough for young roots to push through, but dense enough to retain water and nutrients. For the best results, rooting media should be sterile, otherwise your cutting may lose its chance at life fighting off pathogens. Too many nutrients in the rooting media can damage or inhibit new roots. [Some plant cuttings can be started in a cup of water, but this can lead to severe transplant shock, once roots have formed and the specimen is placed in actual soil. If you use this method, be sure to change the water every week and transplant very gently.]

Since each plant has its own Perfect World, you will have to research each species individually, but they are all more likely to succeed when cuttings are taken first thing in the morning.

How to take a cutting

To ensure your cuttings can survive the process, always use a very sharp knife or razor that has been sterilized in rubbing alcohol. This will prevent the spread of disease to the cutting. Tearing or using shears to remove cuttings does not leave a smooth edge and plants tend to be unable to heal quickly enough to start growing. Remove any existing flowers and flower buds. If leaves are particularly large, they can be reduced in size to allow for better air flow while still allowing photosynthesis to occur. To speed the rooting process, you can dip the cut end in rooting powder, which may or may not contain a fungicide.

Cuttings can be an excellent way of continuing the line of a preferred plant without spending any money.

Diamondback moths are common pests of cole crops.

Cole crops include broccoli, Brussels sprouts, cabbage, cauliflower, and Napa cabbage. That’s where I saw the damage. My Napa cabbage was growing very nicely, enjoying our cool winter weather, but the leaves looked more like Swiss cheese. That’s because diamondback caterpillars prefer older leaves, so the first sign of infestation you will see is a bunch of holes in the larger leaves. They also feed on flower buds and flower stems.

Diamondback moth lifecycle

Adult diamondback moths (Plutella xylostella) lay their eggs on the underside of leaves and they are very difficult to see. When the eggs hatch, tiny caterpillars burrow their way into the crown for safety. When a diamondback moth caterpillar is disturbed, it will jump ship, rappelling away from danger using a thin silken thread to swing to safety. After feeding for a couple of weeks, diamondback moth caterpillars spin a loose cocoon on nearby leaves or stems, where they pupate.

The word dandelion, which means lion’s tooth, actually refers to several different plants in the sunflower family. Native to Europe and Asia, dandelions have been following humanity across the globe, taking advantage of soil disturbed by agriculture, fires, and construction. This makes them a ruderal species. Ruderal species are the first plants to colonize disturbed land.

Bane of lawns everywhere, the common dandelion (Taraxacum officinale) was brought to North America in the 1600s to be used as both food and medicine. The species name officinale refers to an early English word meaning medicinal.

Dandelion plants
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Cousin to lettuce and chicory, dandelions are easy to recognize, with their low-growing (basal) rosette of toothed leaves and bright yellow or orange composite flowers. Composite flowers are actually made up of several florets, clustered together. Dandelion florets reflect ultraviolet light, which attracts many beneficial insects, looking for nectar and pollen. Surprisingly, dandelions do not need to be pollinated to set seed. Instead, seeds are produced asexually, in a process called apomixis. As a result, all offspring are identical to the parent plant. Besides the floral stem, dandelions are acaulescent, which means they appear to not have any structural stems.

​Dandelion flowers

Dandelion flowers open each morning and then close each night, in a behavior called nyctinasty. Each plant can produce up to ten floral stems. The cuplike structure seen at the base of each dandelion floret is called a calyculus. Once the flower has matured, it will begin to dry out. After the dried petals and stamens fall off, specialized leaves, called bracts, curve backwards, exposing the seed ball. Each stem produces a single seed ball. These seed balls are commonly called blowballs or clocks. The seeds we see are actually a special type of fruit, called a cypsela. The feathery bristles that act like a sail are called pappi (pappus, singular). The hollow flower stem contains a bitter latex used to defend against herbivores.

​Dandelion latex

Latex is used to make rubber. While most of the latex used to make rubber today comes from the rubber tree (Hevea brasiliensis), you can make your own rubber from dandelion latex! You can make an elastic band simply by coating your finger with dandelion latex, allowing it to dry, and then rolling the latex off your finger. Voilà! You can also make a bouncing ball or waterproof fabric out of dandelion latex. [Did you know that a man named Charles Macintosh figured out how to smear latex between two pieces of fabric to make waterproof fabric? That’s why raincoats are often called macintoshes!] When dandelion latex dries, it stays sticky until it cures. Curing latex involves applying heat and sulfur. The curing process removes the stickiness. Dandelion rubber is stiff in cold temperatures and supple when it is warm. Only Russian dandelions make a latex that is strong enough to be used commercially. [I just learned that one company is researching the use of Russian dandelion latex to make automobile tires!]

Dandelions as food

All parts of the dandelion plant are edible, but you may want to harvest the newest leaves to avoid some of the plant’s bitterness. Eaten the same way as spinach, dandelion greens are packed with good nutrition, including high levels of vitamins A, B, C, and D, according to the University of Maryland Medical Center. Dandelions also contain a lot of iron, calcium, potassium, and zinc. Young dandelion roots can be peeled and eaten. They are said to taste like turnips, but I haven’t tried them yet. The roots can also be roasted and used as a coffee substitute. The flowers are also edible. They can be sautéed in oil with a little garlic and they can be used to make dandelion wine.

Dandelions as medicine

Traditionally, dandelion has been used to treat infections, digestive problems, as a mild laxative, and to stimulate the appetite. Dandelion leaf tea was said to “purify the blood” and the milky latex was used as both mosquito repellent and wart remover, though I couldn’t find any scientific proof to back up any of these claims. According to WebMD, no research has demonstrated any verifiable medicinal use of dandelion, though it does contain chemicals that decrease swelling and increase urine production.

Dandelion roots

These herbaceous perennials have taproots that are strong enough to counteract compacted soil. Hell, they can break through concrete! While dandelion roots are typically only 6 to 18 inches deep, some specimens go 10 to 15 feet deep! Dandelion plants can live for up to 10 years and reach 20 inches in diameter.

I used to try to eliminate dandelions from my lawn, despite my love for their bright yellow flowers and the irresistible seed heads. I finally decided to try putting the plants to work for me in my heavy clay soil. While mulching and growing green manures and cover crops has significantly reduced soil compaction on my property, I have a theory about dandelion taproots. It goes something like this: Since dandelion taproots are strong enough to break asphalt, I allow them to grow, regularly removing the greens (for salads and as a treat for my chickens), before flowers emerge. My theory is that the dandelion taproots will dig down into my compacted soil, bringing microorganisms with them, to create healthier soil. Even if it doesn’t work, I still get pretty flowers and edible greens. Maybe I’ll even try making dandelion wine, one of these days. If my theory is wrong and I end up with a severe problem with dandelions and other, similarly growing weeds, I make have to resort to other control measures.

Dandelion control

If you really must get rid of the dandelions in your lawn, it will take consistent effort on your part. As you already know, those seeds can blow in on the wind from miles away. This battle never ends. While herbicides will certainly kill individual dandelions, those same chemicals can be toxic to other living things, such as us, and our pets. Maintaining a healthy lawn and removing plants as soon as they are seen is the best control method. Cutting off young plants at ground level, a practice called grubbing, is effective only if you are diligent. Crabgrass preemergent herbicides advertised as effective against dandelions do not prevent seeds from germinating.

Love ‘em or hate ‘em, dandelions have been around for 30 million years, and they are here to stay.

You may as well make the most out of these common weeds.

Aphids, or plant lice, are nearly always a problem, here in San Jose, California. This is particularly true when it comes to cabbage aphids.

Cabbage aphids (Brevicoryne brassicae) can wipe out a cabbage crop before it ever gets started. Native to Europe, this pest of cole crops is now found throughout the United States.

Controlling cabbage aphids
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Prevention is key to cabbage aphid control. My cauliflower plants, which had been protected under row covers, were left untouched, while my cabbages and broccoli were hit hard. Once aphids are seen, you can often use a strong spray from the garden hose to dislodge them. If that doesn’t work, insecticidal soaps can provide some control. Since soap may be phytotoxic, especially on cabbage and Brussels sprouts, it is a good idea to apply them on a foggy day. Also, remove any weeds in the mustard family from the area. Cabbage aphids can hide out in the mustard and then return to your garden. Pesticides can be used, as a last ditch effort, but aphids are developing resistance to these chemicals and that can be a dangerous spiral.

Another problem with using pesticides against cabbage aphids is that those same chemicals also kill beneficial, predator insects, such as lady beetles, parasitic wasps, and the syrphid fly (hoverflies). These helpful insects are natural predators of caterpillars, imported cabbageworms, diamondback moths, loopers, and armyworms, which can cause other problems for your cole crops.

Monitor your plants every couple of days and be on the lookout for cabbage aphids!

Since plants are unable to relocate, they must adapt to their surroundings.

Before we start exploring plant adaptations, let’s make one thing clear: plants (as far as we know) do not ‘decide’ to do anything. Genetic mutations are happening all the time. In some cases, a mutation occurs that makes a living thing better suited to its surroundings. Plants that develop beneficial mutations live long enough to reproduce, while those that don’t, well, they don’t.

It’s a basic rule of evolution: What works, is. What doesn’t, isn’t.

Types of adaptations

Plant adaptations are categorized as behavioral, physiological, or structural. These adaptations can make a plant better suited to its environment, more likely to get the food and water it needs, or better able to ensure genetic survival of its species.

• Behavioral adaptations include the way plants lean or grow towards the sun and the way roots go down, into the soil. Some plants produce a single large crop of fruit while others produce and ongoing continuous crop (determinant v. indeterminate). Some plants even have feeding behaviors that lure and trap insects for food.
• Structural adaptations - A plant’s structure determines how much sun it can reach, and how the sun’s energy is absorbed. Structures, such as spines and thorns, can protect against grazers, while other structures make seeds stick to passersby or fly on the wind. The bright colors fruit and flowers are structural adaptations that increase the likelihood of seed dispersal.
• Physiological adaptations - Some plants produce toxins, such as poison oak and poison ivy, to protect themselves, while others produce chemicals that taste bad. In some cases, such as black walnut, the plant produces a chemical (juglone) that prevents other plants from growing nearby. If you’ve ever brushed against, or tried picking, a stinging nettle, you have probably learned the  hard way that these plants have hollow hairs that break off easily, injecting a stinging acid into your skin. Plants that have special tissues for absorbing and storing water is another physiological adaptation.

The easiest way to see a variety of plant adaptations is to look at the ways plants adapt to their surroundings. Depending on where a plant grows, certain adaptations can come in handy.

Biome adaptations

Biomes are large, naturally occurring communities of plants and animals found in a specific environment. Each biome has its own characteristics that require different adaptations for a plant species to survive and thrive.

    Deserts - Scorching heat makes water retention a priority. Succulents store water in their leaves; waxy cuticles reduce water loss; leaves stay small; flowers bloom quickly after a rain; deep roots find underground water; fast-acting surface roots collect dew and rainfall before it evaporates; hairy leaves help shade the plant; spines reduce grazing; and blooming at night attracts pollinators that are not active during the day.
    Grasslands - Hot summers, cold winters, and the threat of fire encourage adaptations such as: deep, extensive root systems; narrow leaves that retain water; soft stems that bend in the wind; and plants that grow from their crown, rather than from stem tips.
    Taiga, or boreal forests - Cold winters, swampy soil with poor drainage, and areas of permafrost make being an evergreen a good idea: waxy, needlelike leaves lose less water; drooping branches shed snow more easily; and coloration is usually dark, to absorb more heat.
    Temperate deciduous forests - Four distinct seasons and plenty of rain make for tall trees: thick bark; shade-tolerant shrubs; flowers that bloom early in the season, before tree leaves block sunlight; broad tree leaves capture plenty of sunlight and then are dropped before snow can weigh them down.
    Temperate rain forests - Heavy rain and steady, cool temperatures make growing slow business: many plants, such as moss, grow on other plants, helping them reach sunlight; tree seedlings often start growing on dead nurse logs, which provide added nutrients.
    Tropical rainforest - Heat and heavy rain are a recipe for pests, diseases, and leaching: these plants use rapid growth, climbing growth behaviors, or other plants (epiphytes) to get at the sunlight; trees tend to have smooth bark, making it difficult for vines to climb and choke them; drooping leaf tips reduce standing water; and above ground roots provide added stability.
    Tundra - Dry, cold conditions make it a good idea to stay low and close to the ground for warmth: fuzzy stems and leaves provide wind protection; dark flowers absorb more heat.
    Water - Plants living in water tend to have flexible stems and floating leaves and seeds.
    
Nutrient scarcity

In some situations, plant nutrients are scarce. Some plants, such as legumes, are able to harvest nitrogen from the atmosphere, while other, such as Venus flytrap and pitcher plants, attract and trap insects for their food. How bizarre is that?

Bizarre adaptations

Now for the really fun stuff. These plants have managed some extreme adaptations. We will start with the Welwitschia, or onion of the desert. Found in Namibia, the Welwitschia has leaves that can be 13 feet long and a stem that can grow to 6 feet in height and over 20 feet in diameter! This plant can live for up to 1500 years, even if it only gets rain every 4 or 5 years.

While longer daylight hours may energize us, it is warmer temperatures that really get plants and insects going.

During colder winter months, most plants and insects don’t do much. It isn’t until a certain number of days are spent within a range of warmer temperatures that growth can resume. This combination of time and temperature is called physiological time. The physiological time needed by any particular organism stays relatively the same, much like the chilling hours required of certain fruit and nut trees to produce a good crop. Physiological time is expressed in degree-days (°D), also know as growing degree-days (GDD).

How are degree-days used?

The number of degree-days needed for any particular species to move from one developmental stage to another (phenology) is still being researched, but you can this information to help you predict germination, vegetative growth, bloom times, and harvest time. Degree-days are also very important when using pheromone traps and other pest controls for things like San Jose scale. Beekeepers are beginning to look into degree-days as a way to predict colony lifecycle.

Temperature thresholds

Generally speaking, degree-days needed by warm weather crops are those with temperatures between 50°F and 95°F, while cool weather crops have a low end temperature of 40°F. These thresholds can also vary by individual species. When temperatures drop below the lowest temperature, called the baseline, development stops. Above that range, development slows or cuts off altogether. Baselines of common garden plants:
   35°F - onions
   38°F - carrots
   39°F - strawberries
   40°F - asparagus, barley, beets, broccoli, collards, lettuce, oats, peas, potatoes, rye, wheat
   45°F - squash, sunflowers
   50°F - beans, corn, musk melons, peppers, sorghum, tomato
   55°F - cucumber, watermelon
   60F - eggplant, okra, sweet potatoes

Calculating degree-days

There are several different models used to calculate degree-days, but, here in the U.S., they all boil down to the same basic idea. Degree-days are calculated first by adding that day’s high and low temperatures and diving by 2 for a mean temperature for the day. A plant’s baseline temperature is then subtracted from that mean temperature, for a number of degree-days counted for that day. For example:
     High 84°F
     Low 54°F        (84 + 54) / 2 = 136 / 2 = 66 mean temperature
     Base 50°F        66 - 50 = 16 degree-days

Unless you really enjoy this sort of thing, you do not need to worry about calculating degree-days for yourself. Agricultural researchers have already done that work for you. You can look up your local degree-days using the UC Davis CA weather data (assuming you live in California). You can also try OSU’s Croptime calculator. Or, you can invest in your own weather station and generate a more accurate, customized model. Since each garden and neighborhood is its own microclimate, the degree-days reported are only estimates anyway, but these estimates can give you the advantage when controlling pests and caring for your plants.

Degree-days to maturity

Most seed packets offer a “days to maturity” number. This number is a statistical average spread out over the entire country. Factor in things like local climate, drought, pests, and disease, and you can see that these averages are only marginally useful. You can use weather station information to generate your own, more accurate days to maturity measurement. Here are the degree-days needed by a few common garden plants and pests to reach maturity:

• Beans           1200 GDD
• Beets            1450 GDD
• Corn             1360 GDD
• Cucumber  1370 GDD
• Grapes         1390 GDD
• Peas              1200 GDD
• Tomatoes    1300 GDD

• Borers            207 GDD
• Cutworms     130 GDD
• Leafminer      250 GDD​

What surprises me is that the number of degree days for common garden plants, pests, and diseases is not yet readily available.

I’ll keep you posted as the research is published.

Saddle up, garden buckaroos!

Today we are going to learn about spurs - fruit spurs, that is!

Fruit spurs are where fruit grows. Sometimes. Sometimes fruit grows on twig tips. And some fruit trees use a mix of the two. This is called their cropping behavior. Knowing which method your tree uses and being able to tell the difference between a leaf bud and fruit spur will help you make better pruning choices when training fruit trees. This is best done while trees are dormant because there are no leaves to block your view.

Instead of doing it the Wrong Way, you can put the branch collar to work for you and train your tree to grow better and stronger.

Once you have plant varieties that work for you, there is often no need to continue buying seeds. Your plants will produce them for free!

There are three steps to successful seed saving: selection, timing, and storage. But, before we learn how to save seeds, we should review some basic information about plant reproduction.

Plant reproduction

Plants produce seeds to pass on genetic information. Those seeds are produced when a female gamete is pollinated. The way pollination occurs, and the plants involved, make a big difference in what the resulting seeds will become:

• Self-pollinating plants produce similar offspring.
• Cross-pollination between plants of the same variety produce similar offspring, while cross-pollination of different varieties creates hybrids.
• Hybrids (F1) do not produce ‘true’ offspring, and future generations tend to lose vigor.

Seeds produced from plants pollinated by insects, wind, and other natural mechanisms are called open-pollinated (OP). Open-pollinated seeds are more genetically diverse, which helps plants adapt to new conditions. As long as cross-pollination between a different variety does not occur, open-pollinated seeds will produce similar offspring. That being said, bees can travel for several miles, carrying pollen, so there is no guarantee of avoiding cross-pollination unless you keep your plants sequestered in a greenhouse. The nice thing is, you may end up with something more beautiful, better adapted, or tastier than what you had before! If not, you can always add it to the compost pile and try again next year. So let’s get started!

Select seeds to save

The first step is to identify which plants in your garden are open-pollinated. You can use seed packets, plant labels, and online receipts to track down this information. Personally, I have a plastic tub that contains all of my seeds and seed packets, so everything is in one place. I put seeds in envelopes and then write what it is, and where and when it was planted, on the envelope. It really helps me keep track of things! Once you have figured out which of your plants are open-pollinated, pick the ones that grow well and taste the best. Be sure to save seeds from more than one plant of a particular variety, to maintain that healthy diversity. Do not save seeds from plants that lack vigor or flavor. One trick I use is I attached colored ribbons to plants that I plan to save seeds from, using different colors to indicate early or late producing.

Seed harvesting

Leave the very best fruits to ripen naturally on your chosen plants. With tomatoes and peppers, you can even let them get a little wrinkly before picking. Then, open the fruit and remove the seeds. With tomatoes, I just drop the gel-covered seeds onto a paper towel and spread them out a little. Next, I write the name of the plant variety on the paper towel and allow it to dry completely before storing. Pepper seeds are just scraped off the white pith and allowed to dry. Peas and beans should be allowed to dry completely on the vine. Keep in mind, however, that this tells the plant it has completed its reproductive cycle and production may begin to lag. Seeds from plants such as lettuce, carrots, and onions can be collected using paper bags tied over the top of the pollinated flower heads. Generally, I do not save those seeds. Instead, I simply let them do their thing naturally. As a result, I have onions, carrots, and lettuces growing all over my property, with zero effort on my part!

Storing seeds

Many people suggest storing seeds in glass jars or plastic bags, after the seeds have dried completely. Unless you are absolutely sure there is no moisture, it is a good idea to include one of those silica packets you find in shoe boxes and jerky bags, just wrap it in a piece of tissue. As you already saw, I use paper envelopes stored in a secure, but not airtight plastic container, that is kept outside year round. My thinking is, this exposes the seeds to as much of the local, natural environment as possible, weeding out the weak through natural selection. However you store your seeds, be sure to label them right away. It helps if you include the plant name and variety, plus the date the seeds were harvested. Older seeds lose their vigor, so you will want to use seeds within one year for the best results. Seeds need to be kept in a cool, dry, dark place to avoid germinating at the wrong time of year or when you’re not looking.

Disease control

Seed surfaces can be contaminated with bacteria, fungi, viruses, spores and nematodes. The inside of a seed can also host pathogens. This is why it is so important to only collect seeds from healthy plants. In a study conducted at UC Davis, it was found that pumpkins exhibiting surface lesions of Fusarium wilt (Fsc 1) could still be used as a safe seed source, while pumpkins that were infected all the way into the seed cavity could not.

Saving your own seeds allows you to encourage the plants that thrive in your garden. Over time, you may even create your own heirloom varieties!

The letters V, F, and N on a seed packet or plant label refer to certain types of disease resistance and pest tolerance.

All of us work to make our plants healthier. At the end of a growing season, many of us save seeds from the very best fruits and plants for next year. [If you’ve never done this before, I urge you to give it a try. I’ll write about seed saving tomorrow.] By saving and planting seeds from the best plants each year, we are choosing specimens that are better suited to our microclimate and personal tastes.

Building better plants

When we save and plant seeds from specific plants, we are cultivating certain characteristics. A more intensive method of building better plants is to purposefully pollinate one plant with the pollen of another. Taken to the far end of this spectrum, we have plants that are genetically modified in the lab. [I used to be bothered by this, until I learned that plants have been doing it to each other for a very long time. See Dodder.] These manipulations are often used to encourage certain characteristics such as color, flavor, days to maturity, disease resistance, or pest tolerance.

Disease resistance and pest tolerance

Some plants are susceptible to certain diseases, while others are not. The same is true for pest infestations. In both cases, you can generally use the disease triangle to reduce the impact pests and diseases have on your garden. The disease triangle consists of the environment, the plant, and the problem. Change one of those three and the problem can be reduced or eliminated. Installing plants that are already resistant to some of your garden’s more common problems can reduce your workload and keep your plants healthier. That’s where V, F, and N come in.

V is for verticillium wilt

The V tells you that a particular plant is resistant to verticillium wilt. Verticillium wilt is a soil-borne fungus that attacks tomatoes, peppers, berries, snapdragon, eggplant, potatoes, and over 300 other garden edibles. Plants infected with verticillium wilt exhibit chlorosis, wilting, and leaf drop as the fungi breed, blocking the flow of water and nutrients through vascular tissue. Verticillium wilt fungi can stay in the soil for several years, so infected plants should be thrown in the trash. If you have a garden patch affected by verticillium wilt, use crop rotation and plant non-host species, such as beans and other legumes, broccoli, corn, and cereal grains. Non-host species are not affected by this disease.

Seeing V, F, and N is not a guarantee. It simply tells you that a particular variety of plant is resistant. Sometimes, that little extra resistance can make all the difference.

​After the flowers have attracted pollinators and fertilization has occurred, caper berries emerge. Caper berries are oblong fruits that contain many seeds. These fruits are also pickled and eaten, along with the leaves. Caper bushes have strong relationships with mycorrhizae (root fungi) that help them extract nutrients from poor soils. Capers grow well on rocky areas and in soils with higher than normal salinity.

​How to grow capers

You can grow your own capers from seed. Simply place fresh seeds in rich potting soil, with good drainage, and add water. Older seeds may have entered dormancy and will need stratification (cold treatment) to germinate. Caper bushes can also be grown from stem cuttings. Stem cuttings are most successful when tender new shoots are used. Instead of producing leaves at leaf nodes placed below the soil level, they produce roots. Rooting powder (auxin) is commonly applied to encourage root growth. Caper bushes produced by cuttings are generally less drought tolerant in their early years than plants produced by seed, so water accordingly. There are poisonous varieties of caper, so be sure to get your seeds or cuttings from a reputable supplier.

Caper bushes love wet springs and hot, dry summers. They grow best in USDA Hardiness Zones 8 - 10, in full sun. While they can tolerate temperatures above 100°F, they do require frost protection. Once a caper bush is well established, the root system and soil level stump may be able to withstand limited freezing temperatures.

Harvesting capers

The smallest, youngest flower buds make the best capers, so daily harvesting is recommended during the flowering season (May through August). When they are ready to pick, caper buds will be dark, olive green, and about the size of a kernel of corn. (They shrink during pickling.) Caper bushes produce curved thorns, so be careful! One of the nicest things about growing your own capers is if you happen to miss a few buds, you end up with beautiful, fragrant flowers! It's a win-win situation!

The tangy flavor of capers is partly from the salt and vinegar used in brining, and partly from the mustard oil produced by the plant.

Did you know that it is capers that give tartar sauce its unique flavor? I didn’t either.
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Note: If you are a Santa Clara County (CA) resident, caper bushes are on the Qualified Plants List for the Lawn Replacement Rebate. It’s an excellent way to get paid to replace your lawn with something more productive and environmentally friendly!

The science of names

Certain scientists, called taxonomists, love to classify things. They use a system of names that show how closely everything is related to everything else, based on shared characteristics. This all started way back in the early BC’s with Dioscorides (die-oh-score-ih-day) and Theophrastus (thee-oh-frass-tis), but Pliny the Elder’s encyclopedic Naturalis Historia (77AD) is recognized as the first attempt at classifying plants (and every other living thing known at that time). It wasn’t until 1753, when Carl Linnaeus published Species Plantarum (“The Species of Plants”) that the world had a comprehensive plant naming system. Since Latin was the language of educated Europeans at that time, it is still used today as the universal scientific language. If you see a plant name followed by an L., you will know it was classified by Linnaeus.

Basic taxonomy

This sorting by shared characteristics files everything into a series of increasingly specialized categories. Here is a list, using the standard garden tomato as an example: 

• Domain (Eukaryota) - Living cells with nuclei
• Kingdom (Plantae) - Plants
• Division (Angiosperms) - Seed-bearing plants
• Class (Magnoliopsida) - Flowering plants
• Order (Solanales) -
• Family (Solanaceae) - Nightshade
• Genus (Solanum) - Woody nightshade (potato and tomato)
• Species (S. lycopersicum) - Garden tomato

If you have a hard time remembering the order of these classification words, try this popular mnemonic: Dear King David came over from Great Spain. Or you can try making up your own!

Under each of these headings, there can be subcategories and super-categories, but don’t let that scare you off. The most important information is what’s on the label. The two Latin words next to a plant’s common name tell you the genus and species of that particular plant.

Genus and species

The first word is the genus, or generic name. This word is always capitalized, and either underlined or italicized. The next word, in lowercase, tells you the species, or epithet. The species is also either underlined or italicized, but it is not capitalized. The genus and species can provide basic information of growth habits and good cultural practices. Once you have a plant’s genus and species, you can get even more information from its variety or cultivar name.

Variety

When a species has a naturally occurring mutation that reproduces consistently, it is called a variety. To indicate a variety, the abbreviation var. is found after the species name. The variety name is not italicized, underlined, or capitalized. Taking the example above one step further, with a red cherry tomato, we have S. lycopersicum var. cerasiforme.

Cultivar

When a mutation occurs as a result of human intervention, be it through selective breeding, cultural practices, or genetic engineering, the plant is called a cultivar. Cultivars are “cultivated varieties” and you will see cv., followed by a name in single quotations to indicate the cultivar. Cultivar names are capitalized, but they are never underlined or italicized. Again, we can use the above example to see the name of my favorite yellow cherry tomato, the Sun Sugar (S. lycopersicum cv. ‘Sun Sugar’).

Scientific plant naming - then and now

In its early stages, plant taxonomy was based on obvious shared characteristics, such as whether a plant produced seeds or spores, was vascular or non-vascular, and whether it was herbaceous or woody. This method worked well enough for a time. With the advent of genetic testing, plant naming, or botanical nomenclature, has gone through some changes. This is why you may see two different Latin names for the same plant. In fact, there are currently several different classification systems vying for dominance in the world of plant names, which is why it took me so long to write this post!

The most important information to take from this post is to take the time to read those plant labels. Reputable growers are far more likely to sell you what is described on the label. Unreliable growers, not so much. Reading the label can give you a starting point when researching plants that you would like to grow in your garden or foodscape.

In some plant descriptions, you may read that they ares “strongly accrescent” or “scarcely accrescent.” What does that mean?

Accrescent refers to a plant or plant part that continues to get larger as it gets older.

Most plants and plant parts are hardwired to stop growing once they reach a specific size. These sizes vary by individuals because of irrigation, nutrition, temperatures, sunlight, pests and disease, but the estimates are generally true. Other plants, or plant parts, never stop growing in size, or they may continue to grow beyond the rest of the plant until some developmental stage is reached.

Degrees of accrescence

The degree to which a plant is considered accrescent can vary quite a bit. In some cases, only the peduncle, or flowering stem, is accrescent, and then only until the flower reaches maturity. These plants are rated as slightly accrescent.

Most commonly, it is the calyx that is accrescent. Calyx, or sepals, are the green modified leaves that surround the base of a flower. The papery covering seen on tomatillos (Physalis philidelphica) is an example of moderate accrescence of the calyx. When the calyx stops growing, your tomatillos are ready to harvest.

Plants that are rated as “strongly accrescent” take the challenge to grow very seriously. These plants just keep getting bigger. Giant sequoias are an extreme example of accrescence.

Understanding accrescence can help you identify unknown plants. It can also help you to know when to harvest your tomatillos!

In the world of plants, climbers have access to more sunlight and better airflow than many of their low-growing neighbors. Plus, these climbers don’t have to invest time and resources into generating a substantial trunk. Most people believe that all climbing plants are vines of one sort or another, but that is not accurate. There is an entirely separate category of climbing plants known as bines.

Bines or vines?
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Vines use specialized stems (suckers and tendrils) to grab tiny handholds on their support, be it a fence, cattle panel, or a tree. Bines grow skyward by winding shoots into a helix around a support. Some people claim that bines spiral in a specific direction because of residing in the northern or southern hemispheres, but the direction of growth is species specific, rather than based on location.

Common bine plants

There are several bines commonly found in gardens and landscapes. The most common garden bines include:

• Bindweed (Convolvolus vulgaris)
• Climbing honeysuckles (Lonicera spp.)
• Hops (Humulus lupulus)
• French beans (Phaseolus vulgaris)
• Runner (pole) beans (Phaseolus coccineus)

Which bines are growing in your garden?

What is agroforestry?

Technically, agroforestry refers to the intentional addition of trees and shrubs into crop and animal farming for economic, environmental, and social benefits. To qualify as agroforestry, four conditions must be present:

• Intentional - combinations of plants and animals are selected and managed as a unit
• Intensive - productivity is managed through cultivation, fertilization, and irrigation
• Integrated - the above- and below-ground aspects of plants and animals are structurally and functionally combined into a single management system
• Interactive - incorporating a wide variety of plants and animals for a mutually beneficial arrangement that is more productive and sustainable than monoculture

There are five different agroforestry systems: alley cropping, forest farming, riparian forest buffers, silvopasture, and windbreaks. In each case, you can take the basic principle and modify it to benefit your home garden.

Alley cropping

The alley cropping method of agroforestry plants fruits, vegetables, herbs, grains and more between rows of immature trees. The trees provide protection while still allowing adequate sunlight to reach the other crops. Growing dwarf fruit and nut trees in your foodscape allows you to do the same thing year after year.

​Forest farming

Forest farming, also known as multi-story cropping, uses the shade provided by a forest canopy to grow herbs and other edible plants, as well as ornamentals, that perform better in shady environments. You can apply the same principle by planting shade-loving and sun-sensitive plants under existing trees.

Each of these agroforestry methods take advantage of natural processes to create sustainable, environmentally friendly conditions that help plants and soil stay healthier, with less effort on our part. These vegetative barriers also reduce erosion, improve air and water quality, increase biodiversity, and provide more opportunities for growing your own food or selling marketable crops.