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Grapes and pomegranates are under attack by grape mealybugs.  Adult female grape mealybug (UCANR) Grape mealybug description Grape mealybugs (Pseudococcus maritimus) are small, white, flat-bodied plant suckers that appear to have a fringed skirt. Grape mealybug lifecycle These pests have two generations each year. Eggs and crawlers overwinter under bark and in crevices. In spring, they emerge and begin converging on young shoots, where they begin to feed. Those early risers then return to the safety of the bark, where they lay more eggs. Damage caused by grape mealybugs Clustered grape mealybugs can open Pandora’s box to fruit rot and other diseases.  Grape mealybugs (UCANR) How to manage grape mealybugs
Natural predators, such as the predaceous gall midge (Dicrodiplosis californica) and the little brown mealybug destroyer (Scymnobius sordidus) can keep these pests under control, so avoid broad spectrum pesticides. If chemical treatments are absolutely necessary, Applaud has been found effective.
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 Western conifer seed bug (Didier Descouens) CC BY-SA 4.0 Native to North America west of the Rocky Mountains, Western conifer seed bugs (Leptoglossus occidentalis) have recently expanded their range to the East Coast and are occasionally found in Europe. Western conifer seed bug description These narrow, shield-shaped insects are brown and average 3/4 to 1” in length. They have the classic tags seen on the rear legs of all leaf-footed bugs and their antennae tend to stick out on either side. Eggs are brown. Nymphs have light-colored legs and look much like assassin bigs, until they start filling out. Conifer seed bug damage These pests generally feed on the sap of developing conifer cones, causing the seeds within to distort and wither. Favored trees include lodgepole pine, white spruce, and Douglas-firs, though red pine, mountain pine, European black pine, Scots pine, and even pistachios are sometimes chosen. They can also vomit up digestive juices that soften hard seeds. I just hope they never find my stone pine! Even worse, conifer seed bugs have been found to use their piercing mouthparts to damage PEX tubing. PEX tubing is similar to PVC and is used to insulate high voltage electrical wires, and to transport offshore oil and natural gas, sewage, and chemicals.  Western conifer seed bug as seen through a window (BMRR) CC BY-SA 3.0 Conifer seed bug lifecycle
Adult female conifer seed bugs lay 200 eggs in rows, usually along needles, leaf midribs, or stems of host plants. In spring, the eggs hatch and nymphs go through five developmental stages, or instars, before reaching adulthood. In North America, there is only one generation a year, but two or more generations have been seen in Mexico and southern Europe. Insecticides are not recommended, though they can be used as a last resort against heavy nymph infestations. It is better to avoid using broad spectrum insecticides. Provide pollen and water for natural predators. Some tachinid flies have been known to parasitize conifer seed bug eggs. Spiders, assassin bugs, and birds also feed on conifer seed bugs.  Fern fiddlehead (Kate Russell) These plants have been around for over 350 million years, long before flowering plants, or angiosperms, made their appearance. Or dinosaurs, for that matter! Ferns are vascular plants that do not produce flowers or seeds. Instead, they reproduce using spores, similar to mushrooms and other fungi. There are over 10,000 known fern species of fern [so far] and some species can live for 100 years. While some ferns are nearly microscopic, others can reach 80 feet in height.  Ferns in a stumpery (Kate Russell) There is a group of ferns (Azolla) found predominantly in water and they do not look like any ferns you might see on land. One in particular, the mosquito fern, is able to fix atmospheric nitrogen the same way land-dwelling legumes do before going to seed. Fern anatomy Ferns have three basic parts: rhizome, fronds, and sporangia. Fern rhizomes come in three forms: erect, lateral, and vertical. Erect rhizomes provide the solid base from which leafy fronds unfurl. Laterally growing, creeping rhizomes move above and below ground and may even climb trees. Vertical rhizomes often look more like the trunk of a tree. Fronds are a fern’s leaves. The leaf stem, called a petiole when referring to other types of plants, is called a fern’s stipe. The flat blade of the frond is called a lamina. The lamina is often segmented into pinnae by short stems called rachides. When a frond first appears, it is tightly curled and called a fiddlehead or koru. Fronds perform photosynthesis and they provide support for a fern’s reproductive sporangia. Black, brown, or orange sporangia are the reproductive structures of ferns. If there are no sporangia present, the fern is sterile. Normally found on the underside of the fronds, spores are formed in the sporangia. A cluster of sporangia is called a sorus. In some cases, a flap of tissue, called the indusium, may cover the sori until the spores are mature.  Tree fern spores (Anca Mosoiu) CC BY-SA 3.0 Fern reproduction
Ferns are unique in their method of reproduction and they are the only plants with two distinct living stages. As each spore matures, it becomes a sporophyte. Sporophytes that land in hospitable environments grow into very tiny, short-lived plants called gametophytes. Gametophytes have two sets of reproductive organs: a female archegonia and a male antheridia. Fertilization can take place within the same plant or between two neighboring plants. This fertilization produces a new sporophyte that grows into an adult fern. Edible ferns While most ferns are not considered edible, they also tend to not be poisonous. There are some varieties of fern that are edible, such as:
As always, do not eat anything you are not sure to be safe. Fern pests and diseases Ferns are naturally resistant to most plant-eating insects. One edible fern in particular, Tectaria macrodonta, has a gene that was transferred to cotton plants, providing resistance against whiteflies! Foliar nematodes (Aphelenchoides fragariae) and soil borne nematodes (Pratylenchus) can sometimes be a problem. Ferns are susceptible to diseases such as bacterial blight (Pseudomonas cichorii or P. gladioli), Pythium root rot, and Rhizoctonia blight. Infected plants should be discarded. Environmental problems, such as drought, which causes greying, and over-fertilization, which results in frond lobing and leaf tip burn, can be avoided with good cultural practices. This means investing in disease-free plants, using only as much fertilizer as recommended for each fern species, and avoiding overhead watering. If you have a moist, shady crevice in your garden, ferns might be just what you've been lookin for!  Wheat infected with take all disease (William M. Brown Jr.) CC BY 3.0 The fungi responsible for take all disease, Gaeumannomyces graminis, is found in the soil. It enters young plant roots and can often be seen as dying patches in a lawn or field. Take all disease symptoms The fungus enters the xylem and blocks the flow of water, causing stunting, yellowing, and reduced tillering. Tillering refers to the way lateral shoots emerge from the base of the stem, a common growth style of cereals. Infected plants mature faster than normal and have bleached seed heads and blackened roots and crowns. Preventing take all disease There are no effective chemical treatments against take all disease available to gardeners. There is a seed treatment that shows promise, so be sure to get certified disease-free seeds from reputable suppliers. Excessive liming and nutrient imbalances exacerbate this disease. If take all disease appears in your lawn, there isn’t much you can do besides improving drainage. If it appears in your barley, corn, millet, rice, sorghum, triticale, or wheat, the best thing you can do is rotate crops. Oats and rye, while cereal grains, are not susceptible to take all disease. Take all disease can build up in the soil, particularly in monoculture crops that are grown in the same place year after year.  Take all disease fungi parasitized by vampyrellids (USDA) There is one soil amoeba that feeds on the take all disease fungi. This unique protozoa is a type of vampyrellid. Vampyrellids are affectionately known as soil vampires because of the way they leave puncture marks in their victims.
Streaked avocado skins may indicate a disease known as sunblotch. And we are not talking about freckles!  Avocado fruit infected with sunblotch (UCANR)
Cause of sunblotch Until recently, sunblotch was thought to be a genetic disease. We now know that it is caused by a viroid. Viroids are the smallest known infectious pathogens and they only attack plants. Unlike viruses, which contain both DNA and RNA, viroids only contain RNA. This particular viroid attacks many tropical and subtropical plants, but it is seen most often in avocados.  Stem infected with sunblotch (UCANR) Sunblotch control
Once a tree is infected with sunblotch, it must be removed and destroyed. This means that prevention is your only real course of action. Sunblotch can be transmitted through infected pollen, seeds, and budwood. You can’t do anything about infected pollen if the source is on someone else’s property, but you can invest in disease-free bare root trees. You can also make sure that any grafting projects you take on involve only healthy trees. And be sure to sanitize your garden tools after working on potentially infected trees with bathroom cleaner or a 9:1 ratio of water to bleach. European fruit lecanium scale might be a long name, but these garden pests can make short work of your pomegranates, citrus, and olives.  European fruit lecanium scale description
European fruit lecanium scale is a soft scale insect. This means the shiny brown convex cover is not as hard as armored scale covers. You can identify European fruit lecanium scales because the brown cover has several ridges on it, while other soft scale insects do not. European fruit lecanium scale lifecycle European fruit lecanium scale larvae are normally found on twigs and small branches. As temperatures begin to rise in spring, they develop the telltale dome-shaped cover. Adult females fill the space under their cover with eggs and then they die. When the eggs hatch, the nymphs, or crawlers, come out from underneath the scale covers and hide out on the underside of leaves. By late July or August, these pests migrate to fruit. There can be two generations each year and most of the insects present will be in the same life stage. Damage caused by European fruit lecanium scale When European fruit lecanium scale larvae feed, they attach themselves to the outside of twigs and fruit and pierce the surface. This causes cosmetic damage as well as providing points of entry for other pests and diseases. Also, European fruit lecanium scale feeding results in the excretion of honeydew (sugary bug poop), which sooty mold fungus finds delightful. The only exception is that scale feeding on pomegranates does not result in honeydew deposits. Instead, tiny piles of sugar are seen. These sugar piles are easily brushed off of twigs and fruit. European fruit lecanium scale controls Natural enemies are the best controls for European fruit lecanium scale. Twicestabbed lady beetles, steel blue lady beetles, and lacewings will all help fight soft scales. You can also wrap tree trunks with sticky barriers to remove the protection (and disease-carrying potential) provided by ants. Finally, prune trees for good air flow and structure to keep trees healthy. European fruit lecanium scale (IPM Images) CC BY-SA 3.0 https://species-id.net/openmedia/File:Parthenolecanium_corni_IPM2168085.jpg Adult cigarette beetles only live for 2 to 6 weeks and they do not eat. They can fly, however. And cigarette beetle larvae are surprisingly destructive.  Cigarette beetle (Andybrookestar, Public Domain) Cigarette beetles (Lasioderma serricorne) favor tobacco, but they can also damage your cereal grains, and oilseeds, such as olive, peanut, soybean, and sunflower. Cigarette beetles will also feed on dried fruit, herbs and spices, such as paprika, cumin, and sage, flour, pet food, and your favorite books, given the chance. Cigarette beetle description These tiny brown beetles look almost identical to drugstore beetles and furniture beetles, with a more humpbacked profile. If you look very closely, using a hand lens, you can see that cigarette beetles have a distinctive club at the end of their antennae.  Cigarette beetle, multiple views (Kamran Iftikhar) CC BY-SA 3.0 Cigarette beetles are tiny. Eight of them could stand, end-to-end, across a dime. But don’t let their diminutive size fool you.
Cigarette beetle lifecycle Adult female cigarette beetles lay 30 to 100 eggs in and around preferred foods. As soon as the larvae hatch, they start feeding and moving around. After feeding and pooping, larvae enter a pupal stage in cocoons made from the foods they infested, making them difficult to see. While insecticides are effective against cigarette beetles, you are better off tossing out infested materials. Vacuuming and pheromone traps can also help control these tiny pests. Mottled, stunted cilantro plants may have apium virus Y disease. Apium virus Y disease is carried by aphids. This viral disease is also found on celery, carrot, dill, and poison hemlock. It can infect parsley, as well, but no visible symptoms occur.  Parsley infected with apium virus Y disease (UCANR) Apium virus Y disease symptoms
Leaf mottling or mosaic patterns, stunting, cleared veins, and leaf distortions are all symptoms of apium virus Y disease. Older leaves may have yellow blotches, brown lesions, and yellow or brown line patterns. Younger leaves show only faint mottling. Lesions may form on petioles (leaf stems). How to prevent apium virus Y disease Since this disease is predominantly carried by aphids, you can help prevent this disease by controlling aphid populations (as much as is possible, of course). The virus can also be carried on clothing and tools, so be sure to sanitize your tools regularly and avoid walking through areas known to be infected. The virus does not remain vital for very long once it is inside an aphid. Creating physical barriers and increasing the distance between potential carriers can reduce the likelihood of this disease. Crop rotation and the CAREFUL removal of poison hemlock can also help control this disease. There are no effective chemical treatments for apium virus Y disease. Heartwood is the dead center of a tree. It is usually a different color from the living wood and it provides the support needed to hold up a tree that might weigh several tons  Section of yew branch showing pale sapwood, dark heartwood, and pith (MPF CC BY-SA 3.0) Tree anatomy
Tree trunks are made up of several layers of tubes, surrounded by an outer layer of bark. These tubes are the vascular bundles that carry water and nutrients to the rest of the tree. One type of tube, called the xylem (or sapwood), pulls water and nutrients up from the roots. The majority of the trunk is made up of xylem cells. Another type of tube, called the phloem (or inner bark) carries the sugars made by the leaves through photosynthesis down into the rest of the tree. [I remember these two by saying, “Food flows down the phloem, while water and food rise in the xylem.”] Just between the xylem and the phloem is the cambium layer. This is where the actual tree growth occurs. At the very center of the tree is the pith, surrounded by layers of xylem cells. As these xylem cells age, they eventually go through chemical changes that make them solid, losing their ability to transport water and nutrients. There is debate about whether or not these cells are still alive. This is the heartwood. Characteristics of heartwood Heartwood is very strong. The amount of heartwood present depends on the species. Some trees, such as ash, maple, and pine, have very thick heartwood. Other species have only a little heartwood. This group includes chestnut, mulberry and sassafras trees. Some tree species have no heartwood at all. Heartwood gets larger over time. Young trees have very little heartwood, whereas older trees have significantly more. Heartwood is resistant to decay, but wood that looks like heartwood might also be infected with disease or dealing with an insect invasion. Louisiana homes built over 100 years ago out of of bald cypress heartwood appear to be as good as new because of the decay resistance of heartwood. The next time you need to remove a large branch or tree trunk, take a closer look at the layers and see if heartwood is present. If you have ever canned jelly or fruit preserves, you have probably used pectin. Pectin is found in many plants and it has some unique properties.  Cell wall and middle lamella (LadyofHats, Public Domain) The word pectin comes to us from the Greek word for “congealed” and with good reason. Pectin converts liquids into jelly, much the way gelatin does, the difference being that gelatin is made from animal skin and bones, and pectin is made from plants.
Pectin is found in most fruits, to one degree or another: But fruits are not the only plants that contain pectin. Carrots hold an average 1.4% pectin. Commercially, most pectin is made from citrus peels and apple pulp. Soft fruits, such as grapes and strawberries also contain pectin, but at very low levels. How do plants use pectin? Pectin is a structural chain of molecules used in cell walls. Pectin is a major component of cellulose, specifically a layer called the middle lamella. The middle lamella is an outer layer to plant cells that is used to bind cells together. This allows plants to grow larger. The level of pectin present in a plant varies over time due to factors such as plant age and seasonal changes. As fruits ripen, the pectin begins to break down, which is why the fruit becomes softer. A similar process occurs during abscission, when parts such as leaves naturally die and fall from the plant. In some desert plants, pectin has been shown to help repair DNA by creating a mucous layer that captures dew. How do we use pectin? Pectin is used for more than jelly making. Pectin also provides dietary fiber and it acts as a thickening agent and stabilizer for desserts, cosmetics, and medicines. Pectin also binds to cholesterol and slows the rate at which we absorb glucose. This is especially true when the pectin is from apples and oranges. You know that old saying about an apple a day? I guess they were right! The pectin found in apple pulp is also one of the best throat lozenges I know. The mucilaginous pectin provides a surprising amount of soothing relief. Next time your have a sore or scratchy throat, skip the menthol (an irritant) and slowly eat an apple. Molybdenum (Mo) is a plant micronutrient. So little is used that they used to be called trace minerals, but that doesn’t mean they are not important. Molybdenum is very important to your plants’ health. #/media/File:Mo_deficienct_maize_subsistence_farmer_Vulindlela_2017_05_09_6666.jpg) Corn plant showing molybdenum deficiency (Alandmanson CC BY-SA 4.0) Generally speaking, molybdenum is plentiful in alkaline soils and tends to be deficient in acidic soils. You can’t know what your soil contains without a soil test from a reputable lab. Those cute, colorful kits from the garden center don’t even test for molybdenum. Even if they did, they are not [yet] accurate enough to be useful. How plants use molybdenum Molybdenum is an essential ingredient to some very important enzymes. These enzymes are used in nitrogen, oxygen, and sulfur cycles. Specifically, molybdenum is used convert nitrate into nitrite and then into ammonia in order to be used to synthesize amino acids. It is also used by the bacteria responsible for converting atmospheric nitrogen into forms usable by plants. Molybdenum is also part of the process that converts inorganic phosphates into organic ones. Cruciferous plants, such as broccoli and cauliflower, and legumes, such as soybeans and clover, and citrus use a lot of molybdenum. Mobile molybdenum Plant nutrients are either mobile or immobile within a plant. Molybdenum is mobile, which means it moves around easily within a plant. This makes diagnosing deficiencies easier because they are most often seen in older leaves as plants pull nutrients to make new leaves. Molybdenum toxicity is practically unheard of, but deficiencies can be a serious problem. #/media/File:Pregermination_maize_2014_05_15_10_38_33_7932.jpg) Premature germination of corn due to molybdenum deficiency (Alandmanson CC BY-SA 4.0) Symptoms of molybdenum deficiency
Without molybdenum, leaves turn yellow and die and flowers may fail to form at all. The yellowing is often along leaf margins and downward cupping may also appear. In some cases, leaves develop a whiptail shape, rather than the leaf’s normal wider blade shape. Corn kernels may germinate on the cob prematurely in a last-ditch effort at reproduction. Legumes will have fewer or no root nodules if molybdenum is in short supply. Again, you don’t know what your plants have access to without an inexpensive, lab-based soil test. Take my word for it, it is worth the effort. Plum pox is one of the most destructive diseases of stone fruits and I hope you never, ever see it.  Leaves infected with plum pox showing vein yellowing and light green to yellow rings (M Fuchs, Cornell Extension) This viral disease affects almond, apricot, cherry, nectarine, peach, plum, and prune trees, as well as some ornamental Prunus species. In 2014, it was estimated that plum pox has cost Europe over $13 billion in crop losses. Plum pox originated in Bulgaria and is found in many parts of Canada, Chile, Europe, India, the Middle East, and North Africa. Plum pox was found in a Pennsylvania orchard in 1999. Less than one year later, the U.S. Department of Agriculture declared an “extraordinary emergency” which gave them the funds necessary to remove and destroy infected and exposed trees. Then, in 2006, it appeared again, but this time in Michigan and New York. The single affected Michigan tree was removed and extreme eradication efforts took place in New York. Plum pox is considered eradicated in that state, as well as in New York. For now. These eradication efforts have cost over $65 million and resulted in the almost complete destruction of the Pennsylvania stone fruit industry. The threat posed by this disease is that severe.  Fruit and pits infected with plum pox (M Cambra, Cornell Extension) Plum pox symptoms
There are multiple strains of the plum pox virus, but the results are always unfortunate for stone fruit trees. Identifying this disease can be tricky. In some cases, the symptoms can be very subtle. They can vary by virus strain and host cultivar. Generally speaking, leaf veins turn yellow and light green or yellow rings may appear on leaves, fruits, and pits. These symptoms may disappear during the heat of summer, only to return in autumn. Leaves may also exhibit crinkling, curling, and puckering. Cultivars with large, showy flowers may become variegated. Fruit may be deformed, turn brown, or develop concentric colored rings. premature fruit drop may also occur. Unfortunately, these symptoms do not usually appear until the infection has been present for 2 or 3 years. During this time, several other nearby trees can easily become infected. Plum pox transmission The plum pox virus can travel long distances on infected plant material and insects. Grafting infected scions can transfer the infection to healthy trees. Several aphid species can carry this virus. How to avoid plum pox If you only buy certified disease-free bare root stock and other fruit and nut trees, odds are pretty good that plum pox will not find your garden {assuming you don’t live where plum pox is already a problem). Placing new plants in quarantine and doing the best you can to control aphids will also help prevent this disease. Efforts are underway to develop resistant cultivars, but those trees are not yet available. Plum pox may not kill fruit trees, but it can reduce production so much that you will probably end up replacing the trees anyway. Infected trees often produce fruit that is misshapen and more acidic than healthy fruits. If you suspect plum pox, please contact your local County Extension Office or Department of Agriculture immediately. Radishes, broccoli, cauliflower, mustards, and other members of the cabbage family produce a special type of seed pod called a silique [se-LEEK] or siliqua [sil-eh-KWA].  Radish silique (Folini CC BY 2.5) What is a pod?
Pods are made from carpels. Carpels are the female reproductive organs of a plant. The pods of legumes are made from a single carpel, while members of the cabbage family produce pods made from two carpels that have been fused. The pods made from fused carpels are called silique. Pods are a type of dehiscent fruit. Dehiscent means that the structure opens spontaneously when its contents are mature. If a pod does not open automatically, it is called indehiscent. In either case, pods are made up of two identical long halves and they contain seeds. Those halves are the outer walls of the ovary. The two halves are joined along a seam, called a suture. Held between those two halves is a ribbon of seed-bearing tissue called the septum. Brassica pods There are two categories of Brassica pods: siliqua and silicula. The difference between the two is simply the pod dimensions. If the length of the pod is more than three times the width, it is a silique. If the length is less than three times the width, it is a silicula (or silicle). If you allow your radishes and other Brassicas to go to seed, you will see siliquae for yourself, plus you will have seeds for next year’s crop! I have always called hairy bittercress the "fireworks weed” because of the way seeds seem to explode in every direction when the plant is touched. I was surprised to learn that this bitter herb is also edible. Let’s see what else we can find out about this persistent weed.  Hairy bittercress (Rasbak CC BY-SA 3.0) Hairy bittercress description Hairy bittercress (Cardamine hirsuta) grows as either an annual or biennial and it is a member of the cabbage family. As such, it has tiny white, 4-petaled flowers. Before the flowers emerge, however, you will see young hairy bittercress plants as small rosettes of oval leaves, growing very close to the ground. This basal rosette continues to grow in circumference until tall stems emerge. These stems may be 3 to 9” long and that’s where the flowers come in. Those upright stems branch in several directions, each with their own flowers and resulting seeds.  Immature hairy bittercress fruit (Public Domain) How hairy bittercress grows
Found pretty much everywhere, hairy bittercress prefers moist soil, open ground, and freshly disturbed areas. Like other weeds, it grows rapidly, often having two generations each year. You may think they have disappeared during the heat of summer but the first autumn rain will let you know that they were merely waiting for wetter conditions. These plants have long taproots. Hairy bittercress seeds are held in capsules, called siliquae. When the fruit within ripens, there are valves on the siliquae that create a tightly wound coil. That’s why, when you touch them, seeds explode in every direction. This method of seed dispersal is called ballochory. Problems with hairy bittercress Once hairy bittercress takes hold on your property, you will be dealing with it more and more each year, for better or worse. Because of its ability to fling seeds near and far, and grow quickly, hairy bittercress often finds its way into your garden on nursery plants. It is far simpler to put new plants into quarantine and monitor for weed growth right along with pests and diseases. Before you shrug off this seemingly minor weed, you need to know that the real problem with hairy bittercress is the fact that it can host some nasty diseases. Specifically, tomato spotted wilt and cucumber vein yellowing can be carried into your garden on hairy bittercress. These diseases can have a huge impact on several of your crops, and not just tomatoes and cucumbers. It is far easier to monitor the ground each spring and autumn for tiny rosettes and then use your long weeding tool to get under the taproot before it takes hold. You’ve probably read dozens of articles and posts about the wonders of dish soap as a pesticide, fungicide, and surfactant in the garden. All of those posts are wrong.
How dish soap works
Dish soap, also known as dish washing liquid, is a detergent. Dish soap helps us get our dishes clean by cutting grease, oil, and wax. Dish soap generally contains colorants, fragrances, bleach, enzymes, phosphates, and rinsing agents. Insects and plants have waxy coatings that are also damaged by dish soap. When this protective coating is removed, infection, pest infestation, and dehydration all become more likely. Dish soap v. insecticidal soap Insecticidal soap is not a detergent. It is a soap made specifically formulated for use on plants. And it must be used properly to be safe for plants and effective against pests. While liquid hand soap is a soap and not a detergent, it contains fatty acids which are phytotoxic, or poisonous, to plants. Before trying a Quick Fix on your edible plants, take the time to research what is really going on. Your plants will thank you.  Borage leaves exhibiting over-fertilization (Kate Russell) Over-fertilization is an increasingly common problem in home gardens. It happens all the time. Your plants start out doing so well. Then they lose some of their vigor. You might see chlorosis (yellowing), cupping, less fruit production, or simply a failure to thrive. What is a gardener to do? The traditional response was to add more fertilizer, manure, or aged compost. And it would work. For a while. Then those same symptoms would return, motivating you to add more fertilizer. And more. And more. Until it reaches the point where no matter how much fertilizer you add, your plants are simply not performing well. In fact, they seem more prone to pest infestations and diseases. How can this be? Balanced plant nutrients Just as we must eat a balanced diet to stay healthy, plants need access to a balance of nutrients. This is true partly because those nutrients are absorbed at the molecular level, as cations and anions, according to their electrical charge. Too many of one charge or the other makes it difficult for plants to absorb what they need. Also, some minerals, such as iron, are needed to absorb and use other nutrients. If there isn’t enough of these nutrients, or if they are made unavailable due to an imbalance, your plants can starve while sitting at a banquet. Mulder’s chart provides an image of what those nutrient relationships look like. Toxic nutrients Too much of a good thing can be a bad thing. In the same way. too much of a nutrient can lead to toxic levels. Phosphorus, for example, is critical to plant growth and photosynthesis and it tends to bind tightly to soil particles. Phosphorus toxicity can lead to severe stunting and it blocks plants from absorbing iron and zinc. Potassium is critical to enzyme reactions and water and mineral movement within a plant, helps prevent diseases, and regulates the rate of photosynthesis. Potassium toxicity causes leaf distortions, chlorosis, and yellowing along leaf margins. Potassium toxicity can cause calcium, nitrogen, and magnesium deficiencies. Similar problems occur when there is too much of any nutrient. Compounding the problem, these excess nutrients often leach into rivers, streams, and groundwater, causing algae blooms that kill fish and create ripples of pollution and threats to biodiversity. Too much of any one nutrient can throw a monkey wrench in the works. Too much of several nutrients can take years to resolve. Is your soil over-fertilized? The first step it to get a soil test. You don’t know what is in your soil without a soil test from a reputable lab. Sadly, those colorful over-the-counter soil tests are not accurate enough (yet) to be really useful. Many universities offer inexpensive soil tests. These tests can save you time and money and help your plants be healthier. Below, you can see my soil tests from 2015 and 2019. In 2015, I learned that the property we bought had been over-fertilized for a very long time. Phosphorus and magnesium levels were critically high, and there was too much of pretty much everything. Except iron.  2015 Russell soil test (Kate Russell) Remember what I said about iron and nutrient absorption? Yep, my plants had been sitting at a feast, unable to do more than nibble. And it showed. The plants in my landscape were prone to fungal disease, borers and other insects, and they simply were not thriving. For four years, I thought I was doing better. I added a little iron. I avoided using any fertilizer, besides blood meal and ammonium sulfate (for nitrogen). But I continued to add aged compost to help reduce my compacted soil. My compost is mostly made up of chicken coop bedding. It ends up that chicken poop contains very high levels of nitrogen, potassium, phosphorus and calcium. While my plants needed the nitrogen, they certainly didn’t need any of the other nutrients.  2019 Russell soil test (Kate Russell) How to correct over-fertilization
Looking at the results of my 2019 soil test, I realized that I hadn’t done nearly enough to correct my over-fertilization problem and had wasted 4 years in the process. Now, to correct the problem, I have stopped using my nutrient-rich compost on the ground. Instead, I am saving it for raised beds and container plants until my over-fertilization problem has been corrected. And that’’s the cure - stop adding nutrients. The other half of the cure for over-fertilization is to remove nutrients by taking plant material out of your yard completely. Instead of grasscycling, bag and remove grass clippings. Or, you can add them to the compost pile or feed them to your chickens. Avoid using the chop and drop method for a while. Plant more heavy feeders, such as asparagus, beans, beets, broccoli, Brussels sprouts, cabbage, carrots, celery, corn, cucumbers, eggplant, garlic, leeks, melons, okra, onions, parsnips, peas, peppers, potatoes, pumpkins, shallots, squash, tomatoes, and turnips. And harvest those crops to within an inch of their lives. Take everything they have to give and get it out of your yard. Armed with the results from my more recent soil test, I am now adding far more iron, to help my plants absorb what they need, and using wood chip mulch to counteract the compacted soil, but these actions will take time to have an effect. To monitor the effectiveness of these new actions, applying more iron and removing more plant material, I will switch to annual soil tests until the over-fertilization problem has been resolved. I urge you to do the same. Raspberries and white spruce share a disease called late leaf rust.  Severe late leaf rust causes red raspberry fruits to rot (UH–CTAHR) Mid to late summer, spores of this fungal disease infect red and purple raspberries. Unlike yellow rust, which produces yellow to orange pustules in early to mid-summer, late leaf rust pustules are generally not seen until mid to late summer. Late leaf rust symptoms The first symptom of late leaf rust (Pucciniastrum americanum) is small yellow (chlorotic) spots on the top of older leaves. These spots generally start to appear in lower portions of the plant, slowly spreading upward, into younger leaves. As the disease progresses, reproductive uredinia form on the underside of leaves, containing masses of spores.  Random yellow spots on the leaf surface may indicate late leaf rust (UH–CTAHR) Extreme infestations can defoliate the entire plant. Fruit and flowers can also be infected, which causes them to rot. Of course, if all the leaves have fallen off due to disease, there probably won’t be any fruit or flowers. If the fruit has already formed, late leaf rust will appear as tiny orange spots on individuals drupelets. Affected fruits will also ripen unevenly.
Late leaf rust lifecycle
Spores of this disease overwinter in white spruce and infected raspberry canes. Spores can also be spread by wind, so the health of your upwind neighbor’s raspberries can have a direct impact on yours. Late leaf rust control Like other rusts, late leaf rust is best avoided by pruning plants for good airflow and avoiding overhead watering. Also, be sure to remove spent canes each year. If any of those canes have been infected, removing them will break the disease triangle. Fixed copper sprays may help prevent and treat late leaf rust. Cow parsnip is not related to the root vegetable known as parsnips, but you can eat them, if you are careful.  Nine-foot tall cow parsnips in Alaska (Beeblebrox) CC BY-SA 4.0 Cow parsnip description True to its Latin name, Heracleum maximum, these are very large herbaceous plants. Reaching over 9’ in height, all parts of cow parsnip are big. Lobed leaves can be 16” across and the typical umbel-shaped flowers of the carrot family are also large, averaging 8” across. These flowers are white and the outer flowers are often larger than the inner flowers. Stems are succulent and sturdy.  Cow parsnip plants (Dcrjsr) CC BY 3.0  Cow parsnip seeds (Walter Siegmund) CC BY-SA 3.0 Uses for cow parsnip Peeled flower stems have been used as food for a very long time. Tasting similar to celery, cow parsnip is also known as Indian celery or Indian rhubarb. The reason for peeling those stems is because the outer layers contain phototoxins that can irritate or burn your skin. Traditionally, infusions of the flowers were used to repel flies and mosquitoes. Before you start rubbing yourself with cow parsnip, be sure to take a closer look. If you see reddish or purplish spots on the stems, and serrated leaves, look out! You have discovered giant hogweed, a far more potent version. Giant hogweed Purple spots and serrated leaves may indicate giant hogweed (Heracleum mantegazzianum), rather than cow parsnip. The sap of giant hogweed contains phototoxins. These defensive oils cause severe burns and blisters when exposed to light.  Red-spotted stem of giant hogweed (I, Liné1) CC BY-SA 3.0 Now, I am not talking about the discrete round blisters of sunburn fame. These are huge, swollen, ugly, painful burns that can leave black or purple scars for years to come. I won’t share photos here, but you can track them down yourself if you need convincing.  Giant hogweed (Fritz Geller-Grimm) CC BY-SA 3.0 This dangerous sap is found on coarse white hairs (trichomes) on stems. It can cause third-degree burns serious enough to land you in the hospital or a burn unit. Giant hogweed has found its way to northern U.S. states. If you see it, report it to your local County Extension Office.
Another toxic plant commonly mistaken for cow parsnip is poison hemlock, also with purple marks on the stem. Bottom line: when in doubt, don’t. Since cow parsnip, giant hogweed, and poison hemlock can all hurt you, to one degree or another, it is a good idea to be cautious and wear protective clothing whenever you might be around them. Conifers produce seeds but not flowers. This makes them gymnosperms. Instead of flowers, conifers produce cones. Botanically known as strobili, cones are the reproductive organs of conifers.  Mature female Coulter pine cone (Didier Descouens) CC BY-SA 4.0 Cone gender There are male cones and female cones. Male cones, called microstrobilus or pollen cones, produce pollen and look very little like the cones we imagine. Male cones are more herbaceous than female cones and they look very similar to one another across species. Female cones are the familiar woody structures that produce and contain seeds. Female cones, also known as seed cones, ovulate cones, and megastrobili, are structurally unique to each species and helpful when it comes to identification. Cone anatomy Female cones are covered with plates called scales. Female cones start out as a central stem covered with bracts. Bracts are modified leaves or scales with a small flower or flower clusters in its axil. The bright red “petals” of poinsettia are not actually flowers. They are bracts. In some cases, the bracts harden and fuse to the woody seed scales. Male cones appear in clusters and are much smaller than female cones. They contain pollen sacs and generally start growing on the end of the previous year’s branches, usually lower in the tree canopy, below female cones. This prevents self-pollination.
Cone and seed development While male cones usually only last one year, it can take 3 or more years for a female cone to fully develop. Once a female cone is receptive and pollination has occurred, it can take up to a year for fertilization to be complete. As seeds develop, some cones will slowly begin to open, while other species need fire to trigger opening. Stone pine seeds, while delicious, require a lot of hard work to separate them from their cones. Some conifer seeds have a wing that allows them to be carried on the wind, while other species rely on animals, such as squirrels, and birds help them disperse. Stone pine seeds, while delicious, require a lot of hard work to separate them from their cones. Types of cones The cones of holiday decoration fame are only one of many different types of cones. The scales can be arranged in one of two ways: imbricate or peltate. Imbricate scales overlap much like roof tiles and are attached along a common axis. Peltate scales do not overlap and are attached from a central point, more like an umbrella. Some cones look more like berries than cones. Araucariaceae (monkey-puzzle tree, kauri, and the nearly extinct Wollemia tree) - fused scales create a spherical cone; imbricate  Monkey-puzzle tree with seed cones (MPF) CC BY-SA 3.0 Cupressaceae (arborvitae, cypress, juniper, redwood, sequoia) - bracts and seed scales are fused; peltate
Pinaceae (cedar, fir, larch, pine, spruce) - archetypical cone; imbricate Podocarpaceae (Prince Albert’s yew, Matai) - many of the scales are fused into a brightly colored, often edible aril; imbricate
Sciadopityaceae (Japanese umbrella pine) - imbricate
Taxaceae (yew) and Cephalotaxaceae (plum yews) - female cones have only one scale, with a single poisonous ovule; the surrounding fruit is sweet but the seed is deadly While not conifers, cycads and welwitschia, or tree tumbo, also produce cones. Tree tumbo plants are considered living fossils and are unique in that female plants produce female cones and male plants produce male cones. How many cone-producing plants do you have? There are many claims about gypsum in the garden, but how many of them are true?  Gypsum (Elade53, Public Domain) Used to make sidewalk chalk, plaster of Paris, and sheetrock, gypsum (CaSO4) is a soft mineral (along with silica and other minerals) that coats everything and everyone who attends Burning Man. Before we decide whether or not it is beneficial in the garden, let’s learn a little more about gypsum.  Gypsum crystals are plastic enough to bend under pressure of the hand (Rama) CC BY-SA 3.0 fr Gypsum description Gypsum, also known as calcium sulfate, is a salt that forms crystals. These crystals are particularly sharp. In Old English, it was known as “spear stone”.  Gypsum crystals in the Cave of the Crystals in Mexico. Note person for scale (Alexander Van Driessche) CC BY 3.0 Unlike other salts, gypsum becomes less water soluble as temperatures rise. Gypsum can take a variety of forms and, depending on the presence of other minerals, it can take on many different colors.
Gypsum in the garden
Gypsum is made of calcium and sulfur, two nutrients important to plant health. In the early 1800’s, gypsum was considered such a fertilizer miracle that smugglers battled local authorities in what became known as the Plaster War. At that time, gypsum was also known as sulfate of lime or lime sulfate. Plants use calcium to maintain cell walls. Calcium in the soil helps build healthy soil structure by binding tiny clay particles into larger clumps called aggregates. Sulfur is an important component of proteins used by plants. As such, gypsum can be beneficial in the garden, but not always. False claims about gypsum Like most other quick fixes, many of the claims about gypsum are based in fact, but taken too far.
Applying gypsum unnecessarily can cause leaching of aluminum, iron, lead, manganese, potassium into local lakes, rivers, and underground water stores. It also interferes with the beneficial soil microorganisms responsible for helping plants absorb nutrients. Applying gypsum to sandy soils can slow the transport of copper, phosphorus, and zinc. Benefits of gypsum All that being said, there is one situation when gypsum can be helpful in the garden. This only occurs when clay soils contain high levels of salt or, more accurately, sodium. These sodic soils can benefit from gypsum applications, in moderation. High salt levels in clay compound poor drainage, often causing heavy crusts to form. Adding gypsum in this situation allows the calcium to bind to the clay, replacing the salt, which is then leached out of the soil over time through cation exchange. Ultimately, this improves soil structure and drainage and reduces salt levels. Adding gypsum to clay without high sodium levels is a bad idea, as it can make alkaline soils even more alkaline. In most cases, plants need a soil pH of 5.5 to 7.0 to thrive. Rather than simply adding gypsum because you heard it was a good idea, get your soil tested, determine your soil structure, and mulch everything with coarse wood chips to improve your soil and help your plants grow. If you happen to find a large, fine-grained seam of gypsum, you are in luck. Because that particular form of gypsum is more commonly known as alabaster. Now you know. |
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