Onion rust is a disease caused by the Puccini all fungus, the same rust fungi that attack roses.
How to control rust
To break the cycle of onion rust, rotate all Allium crops every 2 -3 years and discard any infected plant tissue. Other common Allium crops include leeks, scallions, and garlic. Avoid excessive irrigation and remove all dead or diseased plant material.
Popular for its crisp, refreshing stalks, celery is a grocery staple in most homes. A specific variety of celery, however, is grown for its roots, rather than the stalks. This variety is called celeriac.
Also known as celery knob, celery root, knob celery, and turnip rooted celery, celeriac (Apium graveolens var. rapaceum) tastes like a cross between celery and parsley. (That’s because celery is a member of the parsley family!) Botanically, celeriac is a biennial, but it is grown as an annual. Biennial plants generally live for two years, going to seed in the second year before dying. Celeriac is very popular in Europe, stores in the refrigerator for months, and is an excellent addition to soups, stews, salads and purées.
How to grow celeriac
Celeriac is easier to grow than celery, but it does have a tendency to bolt in hot weather. It grows best in in USDA growing zones 7 and higher. In our hot, dry region, celeriac is an excellent winter crop that is best started in late summer or early fall. Celeriac seeds are more likely to germinate if they are soaked overnight before planting. Seeds should be started indoors or in a protected area. Plant seeds no more than 1/8” deep and keep the soil moist until germination occurs by covering the soil with burlap, seed cloth, or vermiculite. Watering from the bottom of the container is preferable to avoid fungal problems. Germination should occur in 21 days.
When seedlings are 2-2 ½” tall, transplant them to a sunny location. Plants should be placed 6 to 24 inches apart. Celeriac is shallow-rooted, so use straw or other mulch around the plants to stabilize soil temperatures and reduce weed competition. The ancestor of celery and parsley was found in marshy areas, so keeping the soil moist and nutrient-rich with compost will improve crop size and flavor. Feeding young plants with fish emulsion every couple of weeks is an excellent way to make sure that they have all the nutrients they need. Lateral leaf shoots should be removed and the root shoulders should stay covered with soil to maintain tenderness.
The large root (hypocotyl) is usually harvested when it is baseball to softball size. Ideally, this is after a light frost, which converts some of the starch into sugar. Before eating celeriac, the brown outer husk is removed, similarly to jicama.
Radishes are probably the easiest and fastest garden vegetable to grow. The most common variety of radish goes from seed to harvest in only 3 - 4 weeks!
How to grow radishes
Radishes germinate quickly, usually within 3 - 7 days, under ideal conditions. Radishes prefer a soil pH of 6.5 - 7.0 and loose soil. Keeping the soil moist will speed germination and initial growth, but too much water can cause root rot. For smaller taproots, seeds should be planted 1 cm deep, while larger radishes require a planting depth of 4 cm. Plants should be thinned to 4 - 8 inches apart, in rows 8 - 12 inches wide. To maintain a constant supply of radishes, you can plant new seeds every few days. This is called succession planting.
Radishes can be harvested when the taproot has reached a desired size or the plant can be allowed to go to seed for its edible seed pods. In each case, timeliness determines taste and texture. Roots and seed pods that are too old will be tough and bitter. Radishes can also be grown as a cover crop to add nutrients and prevent erosion, or as a forage crop, to feed livestock.
Because radishes grow so quickly, there are very few pests or diseases to worry about. Flea beetles may chew holes in young leaves, the swede midge (Contarinia nasturtii) may damage foliage or growing tips, and the cabbage root fly larvae may infest the taproot. In each case, good sanitation and keeping the plants healthy are the best defense. Radishes and other cole crops should not be planted in the same location more than once every 3 - 4 years to prevent the spread of disease. Regular crop rotation often breaks up the factors that make up what is called the Disease Triangle.
Radishes as companion plants
Radishes are often planted along with corn, squash and cucumber, which provide welcome shade. Radishes are said to repel cucumber beetles, squash bugs and squash vine borers, but I don't know if that is true. If nothing else, planting radishes makes efficient use of the soil around these larger plants. Some sources claim that radishes repel tomato hornworms, ants, and aphids, but I could find no scientific research to verify these claims.
All plants need sunlight for photosynthesis, but some plants actually perform better in partial shade. If you have shady areas in need of plants, read on!
Partial shade edibles
Most partial shade edibles end up producing more vegetative growth (leaves and stems) than flowers, fruits, roots, and bulbs when given too much sun. These plants prefer a more protected location:
There are even edible plants that can produce food with only 2 - 4 hours of sunlight. The shade-loving plants listed below can also be planted under the shade of taller sun-loving plants. This scaffolding reduces water loss and weed growth, while stabilizing soil temperatures.
If you grow asparagus, you probably have asparagus beetles.
There are two basic forms of asparagus beetle: Crioceris asparagi, and the spotted asparagus beetle, C. duodecimounctata. Asparagus beetles are not normally a problem in California, but it is a good idea to know what to look for in case populations become troublesome.
Asparagus beetle damage
Asparagus beetles feed on the tips of delicious young shoots, leaving scars and blemishes. Later in the growing season, they will feed on stem surfaces and leaves. Larvae may feed on the ferns, leaving a bleached appearance. Asparagus beetles can kill a plant.
How to repel asparagus beetles
Remove damaged spears to prevent other infestations or infections. Remove beetles by handpicking and wash eggs and larvae from plants with a strong stream of water from a hose. Remove aboveground growth in late fall to eliminate overwintering sites.
Basil, parsley, tomato, and nasturtium has been shown to repel asparagus beetles, making them good companion plants for asparagus.
Reliable soil tests are the only way to really know what is in your soil.
Before adding fertilizer to a garden, it is really important to know what is already there. Whether you are growing grapes, tomatoes, or herbs, the nutrients and the microbes in the soil dictate how well those plants will grow. As much as we would all love a convenient, reliable, over-the-counter soil test, it doesn’t exist (yet).
Feeding the soil
Plants use 17 elements to grow. Oxygen (O), hydrogen (H) and carbon (C) are taken from air and water. The other elements (minerals) are absorbed from the soil with the help of microorganisms. There are three primary nutrients: nitrogen (N), phosphorus (P) and potassium (K); three secondary nutrients: calcium (Ca), magnesium (Mg) and sulfur (S); and eight micronutrients: boron (B), chlorine (Cl), cobalt, (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn).
In the 1940’s and 50’s, the idea of “better living through chemistry” led to tons of chemicals being added to agricultural soil. Some of it worked and some of it backfired. The current view is “better living through biology”, which means learning about natural plant life cycles, identifying which nutrients are currently available to plants, and finding natural ways to add whatever is needed.
Time soil tests for the best results
The results obtained from a soil test are not written in stone. Conditions in March will be far different from those in July. Variables such as temperature, moisture, and the molecular exchanges (cation exchange capacity) that are occurring all the time underground can change which nutrients are available to your plants. This is especially true for nitrogen. Signs that a soil test is needed:
How to red soil test results
The funny thing about soil chemistry is that the absolute measurements are not nearly as important as the ratios between certain elements. For example, my soil test showed an abundance of every nutrient needed by plants except one: iron. Unfortunately, iron is needed by plants to help them absorb practically everything else. In effect, my plants were sitting at a banquet with their mouths taped shut! By spraying the leaves with foliar iron, which plants can absorb through their leaves, they then had the iron they needed to make everything else available.
Laboratory soil test results will show two figures for each element reported. One figure is the recommended range and one is what is in your soil. Hopefully, they will be relatively close. If your garden has plenty of a nutrient, it is a waste of time and money to add more. In fact, adding more can compound ratio problems that make nutrients unavailable to plants. And don’t be surprised if your soil test lab does charges extra for nitrogen testing.
Nitrogen is a very fickle, fleeting element that is here and gone before you know it. It is worth the extra cost to find out what current nitrogen levels are, but keep in mind that those figures are only relevant for a few days, since nitrogen responds quickly to changes in temperature and moisture. Nitrogen is the single most limiting factor in plant growth. Regularly adding aged compost and treating with blood meal, cottonseed meal, alfalfa meal, feather meal or fish emulsion can help maintain nitrogen levels.
Do regional differences matter?
Before sending a soil sample to the cheapest lab, keep in mind that regional differences may impact your results. As quoted from the University of Massachusetts (my go-to lab):
“The UMass Soil Lab accepts soils from all over the continental U.S. However, we use the Modified Morgan extracting solution for nutrient analysis. This extracting solution was developed for New England's sandy, acidic soils, and climate. Additionally, lime and fertilizer recommendations are intended for soil conditions and climate in New England. While useful information can be obtained by getting a soil test at UMass, differences in soil types and growing conditions need to be taken into account when interpreting test results and recommendations.” That being said, the UMass soil testing lab is highly respected. Simply use the results with a grain of salt, or find a local lab.
Rather than wasting time, money and effort by gardening blindly, a good soil test can help you decide which elements are needed and protect the environment and ground water supplies from excess chemicals and nutrients.
While not always a good idea, squashing bugs is the perfect plan when it comes to these garden pests.
If you planted squash in spring, you may be seeing squash bugs in July. Squash bugs (Anasa tristis) use piercing mouthparts to suck plant sap from members of the cucurbit family. This includes melons, pumpkins, summer and winter squash plants.
Damage caused by squash bugs
Plants infested with squash bugs exhibit speckled leaves that begin to wilt as feeding increases. This wilting may resemble the bacterial wilt spread by cucumber beetles. Squash bugs may also feed on and kill young fruit.
How to control squash bugs
Sanitation is the best squash bug control method. These pests overwinter under plant debris. You can take advantage of this behavior by leaving small planks out in the garden. In the morning, look underneath the planks and kill any squash bugs found underneath. Also, companion planting research has shown that planting marigold, nasturtium, mint, and radish nearby can repel squash bugs. Trellising your cucurbits can make the environment less hospitable to squash bugs.
Pirate bugs are tiny predators that can inflict a painful bite.
But, before you try evicting pirate bigs from the garden, it is important to know that pirate bugs are your best defense against thrips.
Sulfur is the stuff of brimstone.
This bright yellow mineral has anti fungal properties that make it valuable to gardeners facing brown spot, crown rot, and other fungal diseases. Sulfur can also be used to acidify soil that has a pH that is too alkaline. Sulfur is an essential nutrient used by plants. It helps plants form proteins and specific enzymes. Sulfur in the soil also helps reduce salt levels.
Creating chemical balance in the garden
Most plants prefer a relatively neutral to slightly acidic pH. Some plants, such as blueberry, prefer more acidic soil. Sprinkling sulfur throughout the garden and then watering it in creates sulfuric acid. This is not the acid that will dissolve your car’s paint, but it will help make many nutrients available to plant roots. Before treating soil with sulfur to adjust the pH, it is important to get a soil test from a reputable lab. Too much of a good thing is a bad thing….
Sulfer as fungicide
Dusting plants with sulfur can prevent or counteract many fungal diseases, such as powdery mildew, brown spot, and others. Fungi generally avoid acidic environments, which is what makes sulfur so effective as an organic fungicide.
Do not use horticultural oil within 2-4 weeks of applying sulfur. Sulfur and horticultural oil combined are phytotoxic (poisonous to plants) when combined. Also, it is better to use fixed copper, rather than sulfur, on apricot trees.
Bindweed (Convolvulus arvensis) is an insidious Eurasian garden and agricultural weed that is frequently mistaken for morning glory because the flowers look very similar.
This invasive weed was first seen in California in 1884 and can now be found growing just about anywhere below 5,000 feet elevation. Bindweed can be particularly troublesome for beans, cereals, and potatoes, but it attacks many other crops, as well. Bindweed can carry viruses that carry tomato spotted wilt, vaccinium false bottom, and potato X disease.
Bindweed is a hardy perennial that grows from rhizomes. It’s seed leaves (cotyledons) look square with a tiny notch at the top. Sprouts that emerge directly from rhizomes do not have cotyledons. Stems are flattened with a groove along the upper surface.True leaves are spade shaped and can be 1/2 -2 inches long. As leaves mature, they become lobed at the base. Stems can grow several feet in length and may trail on the ground or climb upright plants (such as my blueberry bushes).
Since bindweed reproduces underground through rhizomes, as well as above ground by seed, it is especially difficult to control. The root system of bindweed can grow as deep as 20 feet! Roots able to bud are found as deep as 14 feet below the surface. The majority of bindweed roots are found in the top 2 feet of soil with most of the lateral roots in the top 12 inches. Due to its ability to overwinter without foliage, bindweed can persist in an area for up to 60 years.
Herbicides may be effective as a suppressant but will not eliminate bindweed. Once bindweed has invaded an area, sheet mulching may be the only organic solution. Bindweed roots are able to penetrate most fabric, plastic and cardboard barriers, so the sheeting material must be exceptionally sturdy to be effective and it must remain in place for at least 3 years.
Monitor for bindweed daily and pull seedlings as soon as they are seen. Bindweed is less of a problem in shaded areas, so dense plantings can reduce bindweed’s success.
Spotted wing drosophila (Drosophila suzukii) is an invasive Japanese fruit fly that attacks cherries and many berries, such as raspberry, strawberry, blueberry, blackberry. The Spotted wing drosophila has also been seen attacking figs, nectarines, and plums. It was first seen in California in 2008 and has become a serious pest.
Spotted wing drosophila identification & lifecycle
Adults fruit flies are tiny (1/16" to 1/8”). They have red eyes and a brown body. Spotted wing drosophila can be differentiated from other fruit flies by a brown spot on the front outer edge of each wing. Like most fruit flies, Spotted wing drosophila only live for a few weeks, but there can be as many as 10 generations each year.
Female spotted wing drosophila use a pointed ovipositor to pierce the skin of healthy fruit and then deposit 1 - 3 eggs in each location. Several females may deposit eggs in the same fruit. The broken skin surface then provides other pests and diseases with easy access. As the eggs hatch, maggots begin consuming the fruit, making it inedible.
Spotted wing drosophila management
Populations are generally not seen until the fruit is harvested. At that point, there is nothing to be done besides harvesting the rest of the crop, before eggs can hatch, and inspecting the fruit for infestation before eating.
Because this pest is relatively new to the U.S., treatments have not yet been identified. Cornell University offers instructions of how to make your own Fermented Dough Insect Trap.
If you see this pest in your garden, please let us know in the comments and call your local County Extension office.
Italian cuisine simply wouldn’t be the same without the heady aroma and complex flavors of dried oregano leaves.
Oregano (Origanum vulgare) is a member of the mint family. Like other mints, oregano is a hardy perennial herb that has a place in any plot or container garden. Oregano is also known as wild marjoram, being a close cousin to sweet marjoram (Origanum majorana). The two herbs are interchangeable in cooking.
The variety of oregano grown determines its flavor. The most commonly sold variety, Origanum vulgare, is relatively bland, as are O. unites and O. syriacum. For the best culinary flavor, try planting one of these oregano varieties:
Origanum v. ‘Kent Beauty’ has a lovely trailing growth habit, making it perfect for hanging gardens and containers.
How to grow oregano
Oregano prefers hot, dry, sunny locations and well-drained soil. Oregano can be grown indoors or out and it performs well in containers. While plants can be started from seed, it is usually easier to propagate oregano using cuttings and root division. In cold areas, oregano is grown as an annual. In spring, seeds can be started indoors and then transplanted outside after the last frost date. Plants should be spaced 12 - 18 inches apart in full sun. Water culinary varieties moderately. Ornamental varieties will need little or no water.
Oregano thrives in soil with a pH between 6.0 - 9.0, making it an excellent choice in areas with alkaline soil. Fertilizer is generally not needed. Plants can grow from 8 inches to 2-1/2 feet in height and width, creating a bushy shrub or a trailing growth, depending on the variety. Oregano flowers are bluish-purple or white.
Oregano benefits from regular pruning. While plants are still small, pinch off tops down to a leaf node to encourage a bushier growth and to prevent legginess. In winter, established plants can be cut back to ground level. Since oregano is food, think twice about using any chemical pesticides.
Oregano pests & diseases
Aphids, spider mites and fungal diseases can all cause problems on oregano. Ensuring good air flow between plants and proper watering make a big difference in oregano health. Too much water can cause root disease. Allow plants to dry out between waterings. Monitor plants for aphids. Aphids can be dislodged with a strong stream of water from the hose. Planting nasturtiums nearby can entice aphids away from oregano. Aphids prefer nasturtiums, so you get more oregano! Row covers can also be used to protect oregano from many pests.
Harvesting & storing oregano
Leaves of oregano provide the best flavor if harvested before the plant goes to flower. Simply grab a handful of stems and cut below your hand. Then, rinse the cut bundle to remove any dust, insects or microorganisms, shake off the excess water, pat dry and gently wrap the bundle with a rubber band. Hang in a cool, dry, shaded area until completely dry, just as you would with lavender, lemon balm, and many other herbs. Unlike basil and rosemary, oregano really gets its flavor punch during the drying process, so fresh use isn’t recommended. Once the leaves have dried out completely, they can be removed from the stems by rolling them between your hands over a sheet of wax paper. Store in a dark, dry location in an airtight container. (I use spice jars that used to hold something else and that have been thoroughly washed and dried.) Properly dried and stored oregano can last for a year.
Oregano as folk medicine
Oregano has been used in folk medicine for a very long time, but there is no scientific proof that it actually helps in traditional treatments for respiratory, digestive, or nervous disorders. Research is being conducted, however, on oregano’s usefulness as an antibacterial and against liver cancer.
In most gardens, oregano can continue for several years, self-seeding it’s deliciousness and pretty flowers with minimal effort and water.
According to Cal Fire, by the end of spring in 2016, there were 66 million dead trees in California, due to drought and bark beetles. In 2014, that number was closer to 3 million.
Bark beetles are a normal part of forest and tree life. Healthy trees generally protect themselves from bark beetles by producing sap that pushes the beetles out. However, when trees become water stressed due to years of drought, they are weakened and unable to fight back. Many residential trees are facing the same water stress due to reduced irrigation, making them susceptible to attack by bark beetles. According to the USDA, bark beetles kill more trees than wildfire in most years. Trees are a big investment and weakened trees can destroy homes and threaten the safety of your family. Find out how to prevent bark beetle infestations to protect your trees.
Bark beetle species
There are over 600 species of bark beetle in North America, with 200 varieties found in California. Normally, bark beetles attack conifers, but they can also be found in redwoods, oaks, CA buckeye, English laurel, and fruit trees. The most commonly found bark beetles in California are the western pine beetle, engraver beetles, Jeffery pine beetle, Ponderosa pine, pinyon pine, mountain pine beetle, and red turpentine beetles. Two of the 20 new invasive species, the red-haired pine bark beetle and the Mediterranean pine engraver, are now attacking the many Mediterranean pines planted throughout the Golden State. Bark beetles are smaller than a grain of rice. They can be red, brown, or black. With a magnifying lens, you can see that their antennae are jointed, with a club shape at the end. Larvae are tiny, off-white grubs that may have a brown head.
Damage caused by bark beetles
When new adults emerge, they leave a buckshot pattern on the bark surface of infested branches or trunks. Bark beetles chew tunnels through the inner bark, damaging the phloem and the cadmium layer, robbing the tree of valuable nutrients and moisture. As bark beetle larvae feed, they also infect the tree with a fungus that slows sap production.
Bark beetles are also vectors for disease. As they move from one tree to the next, bark beetles expand their own infestation along with whatever disease they may be carrying. Bark beetles are responsible for spreading the devastating Dutch elm disease. Bark beetles are attracted to open tree wounds, such as those that occur when pruning.
Identifying bark beetle infestations
Different species of bark beetle attack different areas of their host trees. Whichever species is active, boring dust mixed with sap is usually the first visible sign. When infestations are suspected, peel off a portion of bark near a boring hole. If bark beetles are present, a winding series of tunnels will be found. Eggs may be present in some of the galleries. Many tunnels will be filled with frass (bug poop). Dead or damaged wood may also be seen. Another common sign of bark beetle infestation is called ‘flagging’, which means the ends of twigs die.
Bark beetle management
Drought-weakened trees that become infested with bark beetles are usually dead within 3-4 weeks.Since bark beetles are protected under a tree’s bark, pesticides and insecticides merely kill off the beetle’s natural enemies, making matters worse.
To prevent bark beetle infestations, it is necessary to keep trees healthy enough to protect themselves. Proper irrigation is critical. Proper irrigation means soaking the soil to a depth of 2-3 feet at a rate appropriate to the size, age, and variety of tree. You can learn more at the UC Page on Irrigation. These tips can also help:
Bone meal is almost exactly what it sounds like: ground up bones. I say almost, because bone meal also contains cleaned slaughterhouse waste products, much the way blood meal is processed.
Bone meal is an organic fertilizer, high in phosphorus (as much as 15%). Bone meal also contains 3% nitrogen. Those minerals are released into the soil at a rate that is dependent on how finely everything was ground up and on soil acidity. Coarse grindings take longer to break down than material that is ground more finely. According to a study conducted by Colorado State University, bone meal labeling can be a bit confusing. They also found that phosphorus from bone meal is only available to plants if the soil pH is below 7.0, something very unlikely in the Bay Area without acidification. At the same time, lavender plants devour phosphorus and may need supplementing.
Before feeding plants or amending soil with bone meal, it is very important to have your soil tested by a reputable local lab. Most Bay area soil is very high in phosphorus, but not always. Unfortunately, over-the-counter soil tests are too unreliable to be worthwhile. Also, amending your soil with bone meal may attract raccoons or dogs, who will dig up your plants in search of a hidden treat that they will never find.
Invest in a good soil test to see if your garden can benefit from bone meal.
Lemongrass (Cymbopogon citrates), is an easy to grow edible that makes an excellent patio, porch, or indoor plant.
Uses of lemongrass
The inner, white core of lemongrass is used in Thai food, marinades, soups, salads, spice rubs, curries, stir-fry and many more delicious recipes. Lemongrass can be used fresh or dried. Lemongrass oil is used as a preservative and as a pesticide. Lemongrass has anti fungal properties, but that trait does not correlate to the yellow mushrooms commonly found in overwatered container plants. This mushroom is considered inedible, so do not eat it. The presence of the mushroom does not affect the lemongrass.
Lemongrass seedlings can be purchased at most garden supply stores, or you can start your own from stalks bought at the grocery store. To use store bought stalks, rinse well and remove any dead or damaged leaves. Put the stalks into a glass with an inch of water in the bottom and place on a sunny windowsill. Roots should begin to emerge after a few weeks. Once the roots are a couple of inches long, gather the stalks in one hand and hold over a medium-sized planting container and use the other hand to add potting soil gently around the roots. You can put some soil in the bottom of the container ahead of time. The important thing to keep in mind when transplanting is to make sure that the crown (the place where the stem connects with the roots) is at soil level. Too low and it will rot, too high and the roots can dry out. Water regularly until the plants are established, then water weekly during summer.
Lemongrass prefers full sun and well-drained soil. It reaches its full size of 3-6’ quickly. If planted in the ground, lemongrass plants should be spaced at least 2 feet apart. Lemongrass grown in containers tends to be somewhat smaller, just be sure to use potting mix that does not contain water absorption crystals. A 5-gallon container is ideal. Aged compost can be placed on top of the surrounding soil to stabilize temperatures and add valuable nutrients. Lemongrass uses a lot of nitrogen when growing, so be sure to feed monthly. Since lemongrass is an edible, blood meal, composted manure, fish emulsion, feather meal, cottonseed meal, soybean meal, or alfalfa meal make excellent, chemical-free sources of nitrogen.
Whether you cook with it or not, lemongrass is a lovely accent plant with a faint lemony aroma.
Succulents are some of the easiest plants to grow. And don’t let those high prices fool you - all you need to do is start trading leaves with friends and neighbors!
Succulents come in a wide variety of shapes, sizes and colors, some of which are really amazing. They make great ornamental additions to the garden because they take very little care and they help prevent erosion. Also, most of them have a spreading growth habit that makes it easy to turn them into living gifts for family, friends, and neighbors.
What are succulents?
Succulents have evolved to store large amounts of water in fleshy leaves, stems, or roots, depending on the variety. This makes them an excellent choice for drought-prone areas. As temperatures rise, the plants absorb this stored water, shrinking the storage area for later use, rather than dropping leaves and making a mess. All plants that can survive in dry environments are called xerophytes. Common characteristics of succulents include:
There is some debate about the difference between succulents and cacti. Basically, not all succulents are cacti, but most cacti are succulents. There is also debate over whether or not the mucilaginous sap of aloe actually does anything, but, hey, if it makes us feel better, that’s good enough for me. Most of these plants are not edible, but some are. Be sure to identify a plant beyond any doubt before trying it for a snack. Some mistakes can be deadly.
Here is a list of the more popular succulents (and where they originated):
If you know of someone who already has succulents, they will probably be more than happy to give you cuttings, baby plants, or leaves, depending on the species. Jade plants, in particular, can be started from a single leaf. Simply place the stub of the leaf on moist, rich potting soil and mist it regularly. Within a week or two, new roots should be visible. Cuttings and baby plants can be propagated in the same way.
Caring for succulents
Succulents can be used as permanent ground cover, in containers, and they make lovely windowsill gardens, as long as they get enough bright sunlight. Succulents prefer well-drained soil, making them an excellent choice for slopes, raised beds, and containers. These tips will help you get the most out of your succulents:
• Avoid planting succulents in low areas where water may collect and cause crown rot.
• Do not place succulents near other plants that require a lot of water.
• Remove any dead leaves to prevent bacterial or fungal disease.
• Adding rocks to the soil can improve drainage and they look nice.
• Stop watering if leaves start to look mushy.
• In winter, cover frost sensitive varieties with lightweight, breathable fabric (not plastic).
• Monitor for slug and snail damage.
Succulent container gardens look lovely year round, and they are surprisingly easy to make. You can see several inspiring ideas (complete with instructions) at the Instructables page on Succulents.
I’d love to see what you do with succulents in your landscape!
Opossums have been around for about 65 million years and they are common garden visitors. But, before you sick your dogs on the only North American marsupial, take a minute to learn about the benefits of this cat-sized rat lookalike.
Opossums (Didelphis virginiana) may have a terrifying set of 50 scraggly teeth, but they provide more help than harm. Opossums are estimated to eat 5,000 ticks each year, along with other garden pests, such as snails and slugs. They also eat frogs and bird eggs. [This can be a problem if you raise chickens. A secure coop goes a long way to prevent disaster.] While an opossum may occasionally eat fresh fruit or vegetables, they usually prefer rotting plant and animal material, so they are helping keep the garden clean.
If opossums have become combative with cats or dogs, it is commonly because they are trying to get at your pet’s food. The easiest solution is to feed pets indoors and remove the temptation.
Everyone has heard of “playing ‘possum” but the truth is even stranger than the fiction. When an opossum is scared or hurt, it literally becomes uncontrollably catatonic, baring its fangs, foaming at the mouth, and releasing a foul-smelling stench from its anal glands, presumably to deter predators. Opossums’ maximum speed is only 7 m.p.h., so this is their only real defense, besides growling or biting. It can take an opossum up to four hours to recover from this involuntary state. Their tiny brains do not have the processing ability to decide to take this action - it is automatic. Opossums do have a surprisingly strong immune system. In fact, they are resistant to snake venom and, unlike raccoons and skunks, are not prone to rabies infections. [Wild dogs are 8 times more likely to have rabies than an opossum.]
There are over 100 varieties of opossum throughout the Americas. All opossums have a semi-prehensile tail (one that can be used for grasping, but not hanging from) and opposable thumbs. Opossums only live 2-4 years, but females may produce dozens of offspring during that time. Opossums start out as bumblebee sized babies that crawl to their mother’s pouch (like a kangaroo), where they will spend the next 11 weeks, nursing and growing. If you’ve never seen a baby opossum, be prepared to be delighted. Seriously! Opossum young are as playful and heart-warming as any kitten or puppy, if you just give them a chance.
In the Deep South, opossum grease was believed to cure respiratory problems when rubbed on the chest, and the meat was commonly eaten. [I think I’ll pass on both counts…]
Deadheading refers to the removal of flowers that are past their prime.
Since the production of flowers is part of a plant’s reproductive process, removing the flowers encourages the plant to produce more flowers, rather than entering the seed-producing reproductive stage.
Highly refined horticultural oils are sprayed onto plants as a pesticide. They are used to control mites and insect pests, and to prevent some fungal infestations.
One big advantage of horticultural oil over other insecticides is that pests are not poisoned, they are suffocated. Chemical pesticides often use deadly chemicals to kill bad bugs, which can then affect human and pet health, as well.
When oil was first used to combat garden and agricultural pests, heavier “dormant oils” were used in the winter, while trees were dormant and leafless, and lighter “summer oils” were used when leaves were present. While both varieties are now much more refined, believe me when I tell you that using dormant oil on leaves in summer is a really bad idea.
Types of horticultural oil
Horticultural oils can be petroleum or plant based. Currently, the petroleum-based horticultural oils provide better coverage without damaging leaves. Most over-the-counter varieties are made from petroleum. Vegetable oils, such as sunflower, soybean, and cottonseed, provide good insect control, but phytotoxicity is a still a problem. Phytotoxicity is anything that is poisonous to plants. Research is continuing. At this time, only Neem oil is a consistently safe vegetable-based horticultural oil, but it acts differently than other oils by adding a naturally occurring chemical to the mix that makes insects ‘forget’ to eat or breed.
How to apply horticultural oil
Horticultural oils are best used when pests are vulnerable. Soft-bodied pests, such as aphids, can be sprayed as populations become troublesome. Scale insects are most vulnerable in the crawler stage, while caterpillars and spider mites are best managed as eggs, in winter and early spring. Heavy infestations of scale insects may require repeated sprayings through June. Once pests have reached a protected stage of growth, such as the hard shell covering over adult scale insects, horticultural oils are not effective. Also, the oil must coat pests completely to work.
WARNING: When applying horticultural oils, it is important that sulphur is not present. Horticultural oils should not be applied 2-4 weeks before or after a sulphur treatment, depending on who you ask. Also, horticultural oils should not be used on water stressed plants. Many horticultural oils are mixed with other ingredients, such as fungicides or insecticides, so it is very important that you read the label and follow the directions exactly, to avoid causing more harm than help.
Most horticultural oils are considered appropriate for organic farming.
Thrips may be really tiny, and they often disappear before you get a good look at them, but they can suck the life from plant leaves, growing tips and buds.
There are thousands of different varieties of thrips worldwide. A few of them are beneficial insects, eating mites and other pests, but most thrips are pests. They are commonly found in greenhouses. These species have piercing mouthparts used to puncture leaves and siphon out nutrient rich sap. Thrips are also vectors for other plant pathogens (diseases).
Thrips are really tiny - often less than 1/20” long. Thrips bodies are thin. They have fringed hairs on their wings, but you won’t see this without a hand lens. Adult thrips can range in color from white, yellowish, pale green, to brown or black. Immature thrips, both larvae and nymphs, look like tiny pale green caterpillars. To make sure that thrips are causing the leaf damage, shake damaged leaves while holding a blank sheet of white paper underneath. A magnifying glass can help identify the culprit. Yellow sticky traps can also help you detect the presence of thrips. If possible, identify the species attacking your plants. Watch this UC video to learn how to collect thrips for identification.
Unfortunately, thrips are difficult to control. Natural predators are your best line of attack, so avoid using general purpose pesticides. This will allow pirate bugs, green lacewings, and parasitic wasps to take care of the problem for you. Thrips have protective larval stages and the ability to fly away, so insecticides are not effective. A strong spray from the hose can displace many thrips. Also, removing weeds and surrounding plants can make life a little less comfortable for these tiny invaders. Once thrips have infested an area, reduce the amount of nitrogen or other fertilizers applied, to limit the amount of vulnerable new growth.
Preventing thrips infestations
Reflective mulch can confuse incoming thrips, but it won’t help once they are established. Row covers can also protect vulnerable plants. When pruning, avoid shearing susceptible shrubs, as this can provide many points of entry, both for thrips and other uglies. Be sure to deadhead flowers and remove dead or diseased tissue, as these areas can also provide a hiding place for thrips.
Healthy plants are better able to defend themselves, so be sure to irrigate properly to avoid water stress.
You can grow a surprising amount of food in your own yard. Ask me how!