It’s Citrus Season by Katie Walter

Anyone with a citrus tree or a friend with one is inundated with lemons and oranges now. Bags of lemons pass from hand to hand for use in lemon curd, limoncello liqueur, lemon meringue pie or just juice for the freezer. Oranges make fabulous fresh juice, putting the store-bought product to shame.

San Joaquin County hosts one of the best climates for homegrown citrus. Except for the occasional freezing nights in December and January when your tree may need a sheet or blanket for protection, citrus love our climate. If the tree is near your home, say against the house or in a corner surrounded by the house on two sides, warmth from the house will likely provide all the protection it needs.

Cold weather recently in Florida was devastating for the commercial citrus crop there. Even occasional freezes are incompatible with large-scale citrus production. A drive to Los Angeles on Interstate 5 shows where oranges and other citrus do well in the Central Valley. The orchards, on the left as you drive south, are a few hundred feet above the valley floor and out of the worst fog and cold. Microclimates matter.

If you are considering taking advantage of our climate and planting a tree or two, keep in mind that oranges and lemons are just the beginning. Limes provide a tart tingle to many drinks and make a delicious soufflé. Grapefruit are yummy for breakfast or in salads. Juice from key limes are the critical ingredient in key lime pie.

Bitter oranges are used for traditional orange marmalade. Kumquats are tiny fruit that look lovely on the tree. They have a sweet rind and sour flesh and make excellent marmalade. The well-named, dark-red blood orange makes fantastic juice. Or you might get exotic and plant the many-fingered Buddha’s hand.

Lemons are probably the most frequently planted citrus here because they are such a versatile fruit. The firm, oval “Eureka” lemon is the one most often found in the grocery store. The round, soft, thin-skinned “Meyer” is the variety typically planted in our backyards and is likely the one in most of the bags being passed around. The juice of the Meyer is much sweeter than the Eureka’s, which makes sense when you learn that the Meyer is a cross between a lemon and either a mandarin orange or a common orange. A very happy accident created our delicious Meyer lemons!

Nurseries and big-box stores are full of citrus trees in pots right now. Full-sized varieties give you lots of fruit but be careful about height. You want to be able to pick the fruit when the tree is fully grown. A dwarf or semi-dwarf variety is just the ticket for easy-to-pick fruit or if you are short on space. Labels on the potted trees are usually excellent for providing information on variety, anticipated size, and cold tolerance. After the tree is home and in the ground, cut it back by about one-third of its height. With luck, the nursery person will be knowledgeable about how much to cut your new tree back.

Don’t expect to get a real crop for two to three years. Don’t let any fruit mature during that period. Pick them early and dispose of them. It takes a few years for the tree to settle in and establish a good root structure. Only then can the tree concentrate on producing high-quality fruit. Bon appetit!

Now for some bad news. You may have heard about the Asian citrus psyllid (pronounced “sillud”) and citrus greening disease, which the psyllid causes. The disease can kill a citrus tree in as little as five years. There is no known cure, although scientists are busy searching for one.

The psyllid is a tiny insect that feeds on all varieties of citrus, in commercial orchards and backyards. It damages the tree by feeding on new leaf growth and by introducing to the tree the bacterium that causes citrus greening disease, also known as huanglongbing. The psyllid first showed up in Asia and had made its way to Florida by 1998. By 2001, the insect was in 31 Florida counties and had spread to Texas. In 2008, the psyllid was Southern California. Today it is widespread in the Central Valley. A diseased tree declines in health and produces bitter, green, misshaped fruit until it dies.

The California Department of Food and Agriculture has undertaken an extensive monitoring program to track the distribution of the insect and disease. Program personnel regularly check yellow sticky traps for the psyllid, in both residential areas and commercial citrus groves, in locations where the psyllid may be spreading. The program also includes frequent testing of psyllids and leaf samples for the presence of the bacterium.

Damaged fruit is safe to eat and not harmful to humans. If you think a tree on your property is affected, do not remove it or any plant materials from the area and call the Department of Food and Agriculture’s Pest Hotline at 1-800-491-1899. For more information on the Asian citrus psyllid and huanglongbing disease, visit: http://www.cdfa.ca.gov/plant/acp.

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or use our website: http://sjmastergardeners.ucanr.edu/CONTACT_US/.

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Gardens as a metaphor for life

An acquaintance recently told me about a favorite and once thriving shrub that was in serious decline.  The problem: over time, branches from a nearby tree had grown and spread so widely that they were shading out the sun-loving plant. The only viable options: severely prune back the mature tree and destroy its structure, or risk digging up the mature shrub and transplanting it to a more favorable location. A major change was needed.

As ambulatory beings, we human beings are fortunate. If an environment is unhealthy or not to our liking, we generally have the option of walking away and putting ourselves in a better place. Not so with plants. They are permanently rooted to one spot—unless we move them—and they must adapt and thrive or wither and die.

In a natural setting, plants are completely at the mercy of environmental factors, living to old age only if conditions are favorable. On the other hand, plants growing in a garden setting rely on their human caretakers to provide for their needs: proper sun exposure, healthy soil, adequate water and nutrients. We must be vigilant over time, watching as plants grow and conditions change, because a landscape (like a growing child) is a living, dynamic, ever-evolving thing.

Commercially-grown plants have been raised under optimal conditions, with carefully scheduled watering and fertilizing, precisely engineered soil mix, efficient pest control, and constantly monitored air circulation. Once they make their way from grower to nursery to home, they must usually contend with less than ideal circumstances.

Annual plants—with lifespans of only a year—usually manage to complete their life cycle even if we mistakenly plant them in a poor place. But other plants—long lived trees, shrubs, and other perennials—need to be monitored to ensure that they remain healthy over the long term. It’s an approach equivalent to an annual medical exam.

To ensure that your garden thrives, begin by following the principle of “right plant, right place.” Each species of plant evolved in its own niche in the world, and thus has its own preferences for soil type (loamy, sandy, clayey, rocky), sun exposure (full sun, partial shade, full shade), water needs (low, moderate, high), heat and cold tolerances, and more. If you duplicate these conditions as much as possible and choose a planting location carefully, your chances of success are high.

Another element of the “right plant, right place” concept involves space. Each type of plant grows to a specific size when mature, so you should take this eventual size into consideration when formulating a planting plan.

A harmoniously designed, pollinator-friendly, well-maintained Mediterranean garden at the Häagen-Dazs Honey Bee Haven in Davis. Plantings include Santa Barbara daisy (Erigeron karvinskianus), (Sedum spectabile ‘Autumn Joy’), Russian sage (Perovskia atriplicifolia ‘Lislett’), Hot Lips sage (Salvia microphylla ‘Hot Lips’), Verbena, and more. (Photo by Kathy Ikeda)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A well-planned landscape should look somewhat sparsely planted in the first year or two. Once plants are well established, they will soon grow to fill in the empty space. Plants that aren’t given adequate space at the outset soon become overcrowded, and this leads to a host of problems: a need for excessive shearing or pruning, which stresses and destroys the natural form of plants; poor air circulation, which can encourage rot or pest infestations; and competition for limited soil nutrients, which results in sickly looking plants or a need for too-frequent fertilizing. (Many commercial landscapes suffer from such overcrowding; they’re planted densely to avoid any bare look from the outset, and that initially pretty appearance steadily declines in subsequent years.)

One approach is to think of a garden as a metaphorical neighborhood. Gardens tend to be at their best when plants are grouped with others that have the same or similar growing conditions, and when they are given space to be themselves. Would you choose to live in a crowded area with aggressive, hostile neighbors? (Wrong place.) Or would you rather be in a place with some space, with like-minded and/or respectful neighbors? (Right place.)

People and plants are alike in many ways. An outdoorsy, sun-loving person won’t thrive in a dark and gloomy office. Someone who prefers cool, shady climates will wilt if relocated to a hot place. Those from dry locales can quickly become depressed when spending time in a rainy, soggy environ. Such comparisons can be extended to the plant world. All living things have specific and very individual needs in order to flourish.

Before you choose a plant, consult a reputable source such as the Sunset Western Garden Book, a knowledgeable nursery professional, or a horticulture specialist. If the size of your site and the planting zone and conditions coincide with the plant’s needs, chances are it will be happy once it’s in the ground… and it will be a beautiful day in the neighborhood.

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or use our website: http://sjmastergardeners.ucanr.edu/CONTACT_US/.

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Dormant sprays can help reduce pests and disease in fruit trees

If you have a fruit tree, you know that gardeners are not the only ones who enjoy the bounty of the harvest.  There are many pests — such as scales, aphids and mites –

Peach Leaf Curl

that feast on the tender plant parts and these same pests overwinter on the fruit trees. Dormant oils help control these annoying pests and are safe for use on fruit trees.

Dormant sprays or delayed dormant sprays are a generic term for an application of pesticides—including fungicides, highly refined horticultural oils and oils in combination with a pesticide– that are  applied to leafless deciduous trees during fall, winter, and early spring. All fruit and nut trees and many landscape trees and roses are susceptible to aphids, mites, scale and specific insect and disease problems affecting fruit quality and tree health

Some dormant sprays are applied to control over-wintering insects, while others are used to prevent disease infection.  While dormant sprays are commonly used on fruit trees, they can also benefit roses and other ornamental shrubs that might develop insect or fungal disease problems as the warmer weather arrives in the spring. Dormant sprays should only be used in conjunction with good garden sanitation. Be sure to rake up and dispose of all fallen leaves and debris that may harbor fungus spores and overwintering insects.

Dormant oil is a refined petroleum product formulated for fruit tree use. It has been in use for well over a century in commercial orchards, and is still regularly used today. It is classified as an insecticide, and acts by coating over-wintering insects hiding in tree trunk and limb bark with a suffocating layer of oil. Oils used at this time of year include insecticidal oils, narrow range, supreme and superior oils. Dormant disease control applications use materials such as copper, lime sulfur, Bordeaux, and synthetic fungicides.

Dormant sprays provide efficient and economical treatment for a number of over-wintering pests and diseases such as: scale, peach twig borer, aphid eggs, leaf curl, powdery mildew and shot hole.

Here is a partial list for fruit trees:

• Apple and pear – dormant oil helps control scale, overwintering aphids, mite eggs and pear phyla.

• Apricot – dormant oil helps control scale, mite and aphid eggs and peach tree borer. Never use sulfur on apricots.

Shot Hole Disease on Apricot

• Cherry – is susceptible to oozing from gummosis (Bacterial canker) and may respond to dormant sprays containing fixed copper.

• Peach and nectarine – require repeated applications of fixed copper spray to control peach leaf curl. In December or January, prune off half to two thirds of last season’s growth to stimulate new fruiting wood. Spray the ground after removing leaves and branches. Use dormant oil if scale is present.

• Plum and prune -dormant oil helps control scale and overwintering aphid and mite eggs. Apply copper for shot hole fungus. Heavy pruning may be needed to help control tree size. Spray ground after clean up.

• Nut trees- remove any nuts still hanging on the tree. Spray with dormant oil to control scale. Oil sprays also help control peach tree borers and mite eggs.

Applying dormant or delayed dormant treatments

A dormant spray may not be required every year in the backyard orchard. For some insect pests and diseases, one dormant application may be adequate with good spray coverage. For other problems, up to 3 applications may be necessary for good control. Decide if you need to apply by noting the amount of insect and disease pressure during the previous growing season. If you decide to spray always read the label and follow the directions, more is not better. Make sure you dress in protective clothing, including long pants, a long-sleeved shirt, chemical-proof gloves, and safety goggles.

Treat at the beginning of dormancy in late November and again just before the buds begin to open in February or early March. One way to remember when to consider dormant spraying is to do so around Thanksgiving, Christmas and Valentine’s Day. Once flower buds begin to open you may damage fruit and kill pollinating bees if spraying is done at this time. Therefore, it is important to spray at the proposed times before “bud break”. Spraying after pruning allows maximum coverage since there are no leaves to block the spray. A good time to spray is right after a period of rain or foggy weather but not during fog, rain or right before a freeze. Avoid spraying trees that are showing signs of drought stress.

Sprays can be applied with a pump sprayer or hose-end sprayer that is sized appropriately for the number of plants you need to spray. The sprayer should be clean, in good working order and not been used for any herbicides.  Spray the entire dormant plant taking care to saturate every branch, stem or cane as insects and the tiny dust-like spores of fungal diseases hide in the smallest nooks and crevices. Don’t use a dormant spray on any plant that has any leaves or is actively growing. Leaves, especially tender new growth, may be damaged by the spray from the impurities in the oils or the reflection of the sun off the oil.

Dormant oils generally won’t harm beneficial insects since they are applied at a time when beneficial insects aren’t present on fruit trees and have a low toxicity level to humans and mammals. Furthermore, dormant oils won’t leave harsh residue behind. It loses its ability to control pests once dried.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  ucanr.edu/sjmg

 

 

 

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Managing Mistletoe in Trees

You may have seen Mistletoe hung in doorways over these past few weeks. It is a traditional holiday decoration, but when it’s growing on trees in the landscape, this parasitic plant may not seem quite as charming.

There are two types of mistletoe: broadleaf and dwarf.

Broadleaf mistletoe (Phoradendron macrophyllum) is an evergreen parasitic plant that grows on a number of landscape tree species in California. Hosts of broadleaf mistletoe include alder, Aristocrat flowering pear, ash, birch, box elder, cottonwood, locust, silver maple, walnut, and zelkova. Other species of broadleaf mistletoe in California include P. villosum, which infests only oaks, and Viscum album, which attacks alder, apple, black locust, and cottonwood.

Dwarf mistletoes (Arceuthobium spp.) infest pines, firs, and other conifers in forests, and can be a problem in forest landscapes such as in the Sierra Nevada foothills.

Leafy mistletoes have green stems with thick leaves that are nearly oval in shape. Plants often develop a rounded form up to 2 feet or more in diameter. The small, sticky, whitish berries are produced from October to December.

Mistletoe plants are either female (produce berries) or male (produce only pollen). The berries of the female plant are small, sticky, and whitish; they are very attractive to birds such as cedar waxwings, robins, and others. The birds feed on and digest the pulp of the berries, excreting the living seeds that stick tightly to any branch on which they land. In most cases, the initial infestation occurs on larger or older trees because birds prefer to perch in the tops of taller trees.

After the mistletoe seed germinates, it grows through the bark and into the tree’s water-conducting tissues, where rootlike structures called haustoria develop. The haustoria gradually extend up and down within the branch as the mistletoe grows. Initially, the parasitic plant grows slowly; it may take years before the plant blooms and produces seed. Broadleaf mistletoes have succulent stems that become woody at the base. Old, mature mistletoe plants may be several feet in diameter, and on some host species, large swollen areas develop on the infected branches where the mistletoe penetrates. If the visible portion of the mistletoe is removed, new plants often resprout from the haustoria.

Dwarf mistletoes are smaller plants than broadleaf mistletoes, with mature stems less than 6 to 8 inches long. Dwarf mistletoe shoots are nonwoody, segmented, and have small scalelike leaves. While broadleaf mistletoe seeds are dispersed by birds, dwarf mistletoe seeds are spread mostly by their forcible discharge from fruit, which can propel seeds horizontally into trees up to 30 to 40 feet away.

Broadleaf mistletoe absorbs both water and mineral nutrients from its host trees. Mistletoes also can produce energy through photosynthesis in their green leaves. Healthy trees can tolerate a few mistletoe branch infections, but individual branches may be weakened or sometimes killed. Heavily infested trees may be reduced in vigor, stunted, or even killed, especially if they are stressed by other problems such as drought or disease.

In newly developed areas or in older established areas where trees are being replaced, the ideal method of controlling or preventing mistletoe is to plant trees believed to be resistant or moderately resistant to mistletoe. Avoid trees like Modesto ash, known to be especially susceptible to mistletoe infestation. Some tree species appear resistant to broadleaf mistletoe. Bradford flowering pear, Chinese pistache, crape myrtle, eucalyptus, ginkgo, golden rain tree, liquidambar, sycamore, and conifers such as redwood and cedar are rarely infested. These or other resistant species should be considered when planting in infested areas, or when replacing infested trees.

For treatment of existing trees it is important to remove mistletoe before it produces seed and spreads to other limbs or trees. Mechanical control through pruning is the most effective method for removal. Growth regulators provide a degree of temporary control but repeated applications are required. Severely infested trees should be removed and replaced with less susceptible species to protect surrounding trees.

The most effective way to control mistletoe and prevent its spread is to prune out infected branches, if possible, as soon as the parasite appears. Using thinning-type pruning cuts, remove infected branches at their point of origin or back to large lateral branches. Infected branches need to be cut at least one foot below the point of mistletoe attachment in order to completely remove embedded haustoria. It is best to call an arborist if mistletoe is infesting your trees and you are unable to reach it to prune it.

Mistletoes infecting a major branch or the trunk where it cannot be pruned may be controlled by cutting off the mistletoe flush with the limb or trunk. Then wrap the area with a few layers of wide, black polyethylene to exclude light. Use twine or tape to secure the plastic to the limb, but do not wrap it too tightly or the branch may be damaged. Broadleaf mistletoe requires light and will die within a couple of years without it. It may be necessary to repeat this treatment, especially if the wrapping becomes detached or if the mistletoe does not die.

Simply cutting the mistletoe out of an infested tree each winter, even without wrapping, is better than doing nothing at all. Even though the parasite will grow back, spread is reduced because broadleaf mistletoe must be several years old before it can bloom and produce seed.

For a list of Certified Arborists in our area or for more information related to mistletoe, you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

This was excerpted from the Pest Notes: Mistletoe by EJ Perry and CL Elmore. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7437.html
 

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Bare Root Season is here—time to plant

A delightfully beautiful rose, 'Double Delight' is a worthy bare-root selection.

Bare root season is here at nurseries and stores and it is a relatively short season. The plants are dug when dormant, hence it lasts from now to about mid-February, so plan to get out and get those plants you want to grow next spring while the selection is at its best. The season is extended somewhat if you buy plants by mail order from colder climates where dormancy lasts longer. Buying bare root plants is cheaper than buying them later when the same plants, not sold by the time dormancy is coming to an end, may be potted up and sold as potted plants. This increases their cost because of the labor and materials involved.

Hence bare root plants are a bargain, there is a wider selection and they won’t be root bound. However, the best reason to purchase bare-root plants is that they establish better when planted in the winter. Although dormant, the roots start to grow first and that can occur in January, so it is a good time for them to be planted and established in their permanent spot.

Common bare-root plants include ornamental and shade trees, fruit trees, shrubs and vines, such as grapes or kiwi. You can also find bare-root artichoke, asparagus, rhubarb, bramble fruits and strawberries. Many roses and perennials are also sold as bare-root plants. Although a bargain, make sure that you buy quality plants. Roots are often wrapped in a plastic bag packed with moisture retaining materials such as shredded paper, wood shavings or sphagnum moss. Examine the packaging closely to make sure that there is a good seal of the plastic bags so that the root packing material has not dried out.

For roses, examine the canes for abrasions, shriveling or other defects and look for at least 3 or more healthy canes. For example, last year when looking at roses in one of the big box stores, I saw roses whose canes were scarred up and down by perhaps the inappropriate or inadequate use of hedge trimmers to cut the canes back when they were packaged. I took a pass on those. I have also seen situations where the roses leafed out in the store and they removed the leaves to keep them looking dormant. Not a good thing to do, nor a great plant to buy.

Before planting a rose or other bare-root plants, it is advisable to hydrate them by soaking in a bucket of water for up to eight hours.  Roses should be planted according to the width that a mature rose will occupy and this should be indicated on the package.  Allow 30 or more inches between most hybrid tea and grandiflora roses, but more for those that grow larger and less for miniature roses. Being able to move around to prune and harvest your roses will be appreciated later.

When planting bare-root roses, form a cone of soil in the hole and spread the roots out over the cone. Prune off damaged roots and shorten any long roots which will wind around in the hole. Make sure the rose bud union is planted an inch or two above the surrounding soil as this will foster new cane growth by exposure to sunlight. You can use a broom or rake handle across the hole as a point of reference for getting the rose at the right depth. Add soil to the hole and then add water as you are filling in the soil to avoid any air pockets, but don’t hard tamp the soil or overwater. Allow for a porous soil structure as roots need oxygen too. This same planting approach is good for most bare-root plants except that only roses need an initial soil cone to spread the roots. It is unnecessary to add fertilizer to the hole when planting.

For fruit and ornamental trees, it is good to dig a wide hole rather than one too deep. A deep hole may cause settling and the graft union might go below ground level later. This increases the chances of crown rot and if the graft gets rooted you may lose the dwarfing effect of the rootstock. It would be advisable to dig deeper only if there is a hardpan that does not permit good drainage.

After planting, it is good to record what was planted by tagging the plant and mapping or journaling what you planted where. Don’t count on remembering 3 years later what the name of that rose was, unless you are blessed with a photographic memory.  Enjoy happy planting.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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Avoid problems with some smaller trees for shade and color.

A friend asked me recently if there are modest sized trees to plant for shade. Her recent experience was removing a Magnolia tree which had cracked up her driveway. The back-hoe operator, who took out the root-ball, said it was the largest he had ever removed. We have to be wary of planting trees that grow too large for their space or so large that they are very expensive to remove them when their expiration date comes around and all living things do have an expiration date. Recently, I removed three large, old evergreen conifers from the backyard of my new home to make room and sunshine for growing dahlias and vegetables. It was costly and made me aware that planting trees that grow to a large size can be a financial loser.

Red maples in my neighbor's front garden.

Eastern Redbud in full bloom in March at my old country home.

When it comes to planting the right size tree and a beautiful one there is a tree that fills the bill and that is Autumn Blaze Maple. It is a patented hybrid of red and silver maples. Whereas red maple (Acer rubrum) is a large tree to 120 feet in nature, the hybrid ‘Autumn Blaze’ (Acer x freemanii ‘Jeffersred’), has a maximum height of 50 ft. It has brilliant eye catching red color, dense branching and rapid growth. It is fast growing, disease resistant, tolerates a wide range of soil conditions, doesn’t drop seed pods and is resistant to car exhaust pollution.

Another red maple cultivar is Acer rubrum ‘columnare’. It grows in a more column like manner, elliptical in form but spreading more in maturity. There is a beautiful pair of red maple trees across the street from my home and I think they have the ‘columnar’ appearance. Unfortunately, they were planted a bit too close to the house, but the current owner didn’t plant them and when he discovered how attractive they are in the fall, he decided not to remove them. For more information on Red Maples, see: https://www.thespruce.com/best-maple-trees-for-fall-color-2130844.

When it comes to selecting smaller trees that work for areas under power lines, PG&E has a list of recommended trees that are under 25 feet for you. You can find more about this and order a brochure from this website: http://www.pgecurrents.com/2013/03/07/in-honor-of-california-arbor-day-pge-says-%E2%80%9Cplant-the-right-tree-in-the-right-place%E2%80%9D/ .

One smaller tree that will not exceed 25 feet is crepe myrtle (Lagerstroemia indica). There are a variety of cultivars and the National Arboretum has released over 24 hybrids selected for cold hardiness, resistance to powdery mildew and other pests, and for varying heights, vigor, habits, flower colors, fall foliage colors, and bark characteristics. All U.S. National Arboretum cultivars have Native American names. Powdery mildew commonly infects older varieties.

Acer palmatum ‘Bloodgood’ is a good small tree for the Central Valley as it handles heat better than some Japanese maples. It will do better if afforded some afternoon shade, but it can handle full sun. It needs moist soil, so is not a drought tolerant variety, but will appreciate mulching to conserve moisture. Its maximum height and spread is about 20 ft.

Easter Redbud (Cercis canadensis) is a beauty when it blooms in the spring. My country home was named Redbud Farm because the original owner had planted several redbuds on the property and they are now very mature trees. They bloom a gorgeous pink for about 3 weeks in the spring before leafing out and they attain a height of about 30 feet and 20 feet wide. Monrovia has a cultivar of the Eastern Redbud that is better adapted to the southwest named ‘Mexicana’ and for other small trees see: http://growbeautifully.monrovia.com/top-13-flowering-trees-for-small-gardens/.  The Western Redbud (Cercis occidentalis) is a native and more drought tolerant than its eastern cousin, with a more intense magenta bloom, but grows more like a shrub than a tree   reaching only 20 feet.

Pineapple guava (Feijoa sellowiana) is an evergreen tree of 15 ft. height and as wide with edible flowers and edible fruit. They are deer resistant, if you live in deer country, and seem to be generally pest-proof. Once established they are drought tolerant and although self-fruitful, I have never had any fruit on my solitary tree so better to plant more than one if you want the fruit. They can tolerate some shade and require only light pruning to shape them. They make a good screen plant and can be pruned into a hedge though not recommended.

Whatever tree you plant, may it be beautiful, small and tidy.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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Master Gardeners – we’re here to help you

The logo for the UCCE Master Gardener Program blends our state flower, the California poppy (Eschscholzia californica) with the pages of a book, representing the program’s focus on horticulture-related education.

Have you ever wondered where to go for advice about landscaping or vegetable gardening? Does a pest problem have you stumped? Do you need guidance on how and when to prune your favorite specimen plant or fruit tree? Master Gardeners are here to help!

The Master Gardener Program is administered by the University of California Cooperative Extension (UCCE), and is part of the University of California, Department of Agriculture and Natural Resources (UCANR). Our mission is “to extend research-based knowledge and information on home horticulture, pest management, and sustainable landscape practices to the residents of California…”

Master Gardeners go through an extensive training program and background screening, and once certified, they must also complete annual requirements for volunteer hours and continuing education. In other words, when you enlist the help of a Master Gardener, rest assured that you’re receiving top-notch assistance.

One of the primary ways San Joaquin Master Gardeners help county residents is through our Help Desk, which is open from 9:00 a.m. to noon from Monday through Thursday. For general gardening questions, you may contact the help line at (209) 953-6112. If you need help with identification of a pest or weed, or diagnosis of a plant disease or problem, it’s best to contact our volunteers by email (anrmgsanjoaquin@ucanr.edu), or to visit our office in person at the Robert J. Cabral Agricultural Center, 2101 E. Earhart Blvd., Suite 200 (off Arch-Airport Road in Stockton). When using email, it’s helpful to send a few clear photos along with a description. If coming to our office in person, please bring an intact insect or a large plant sample in a tightly sealed clear plastic bag or jar, to prevent potential spread of a harmful condition or invasive pest.

Our “UCCE Master Gardeners of San Joaquin County” website is another key part of our outreach, with countless articles, helpful links, and other garden-related information appropriate for our area. The information available is far too extensive to list here, so set aside some time to visit our site and explore its many resources.

A San Joaquin Master Gardener working in the Learning Landscape (photo by program coordinator Marcy Sousa)

Your local Master Gardener volunteers also participate in many local community education projects. These currently include:

  • The Learning Landscape, our volunteer-maintained demonstration garden at the Robert J. Cabral Agricultural Center (address above). This garden is open to the public year-round, and its six miniature landscapes—All-Stars, California Native, Edible, Foliage, Mediterranean, and Pollinator—are designed to inspire and educate visitors. Plant specimens are labeled with both scientific and common names; informative signage explains the garden’s sustainable design elements and irrigation system. Visit the landscape on your own, or look for notice of our biannual public event: Open Garden Day, held in both the spring and fall.
  • Garden Notes, our quarterly newsletter. Both current and prior issues are available online; visit our website and click on the newsletter link on the home page.
  • The “What’s Growing On” blog—of which this article is a part—which is a series of weekly articles on a wide variety of garden-related topics. The full series of articles is available at http://blogs.esanjoaquin.com/gardening/.
  • Monthly workshops in Stockton and Manteca. Check our online “Calendar of Events” for locations, dates, and times.
  • The annual Smart Gardening Conference, which is next scheduled for March 3, 2018. Specific details and registration information will soon be posted on our website.
  • The School and Community Gardens Committee, with expert consultants that can help your organization establish and properly maintain an edible or ornamental garden. We currently work with the Boggs Tract Community Farm, the Stockton Emergency Food Bank garden, the garden at the LOEL Senior Center in Lodi, the Black Urban Farmers Association, and many other school and community sites throughout the county.
  • Community outreach. San Joaquin Master Gardeners volunteer their time and talents at various special events throughout the County: farmers’ markets in Stockton and Tracy; AgVenture programs in Lodi, Manteca, and Stockton; Arbor Day events throughout the county; Stockton’s Earth Day Celebration at Victory Park; the Sandhill Crane Festival in Lodi; and many more.

The statewide Master Gardener program also has a tremendous selection of online resources and other valuable information for the general public. Visit their website (http://mg.ucanr.edu) and click on the “Gardening Resources” icon to access a page with links to:

  • The California Garden Web, a portal to UC’s collection of garden-related research.
  • The California Backyard Orchard, with guidance on growing fruit and nut trees at home.
  • Integrated Pest Management (IPM), on how to cope with garden problems while minimizing impacts to the human and natural environs.
  • ANR Publications, with a wealth of UC-published books and pamphlets.

Master Gardener volunteers throughout California have donated nearly five and a half million hours of their time—and San Joaquin Master Gardeners have donated almost 49,000 hours in the last ten years— to help people like you with garden-related questions and issues. We’re always glad for opportunities to serve you, because gardening is our passion!

If you have any questions about the San Joaquin Master Gardener programs mentioned above, need help with gardening-related questions, or would like to become a Master Gardener yourself, please call our office at 209-953-6100, send us an email at anrmgsanjoaquin@ucanr.edu, or visit our website. 

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Dormant sprays can help reduce pests and disease in fruit trees

If you have a fruit tree, you know that gardeners are not the only ones who enjoy the bounty of the harvest.  There are many pests — such as scales, aphids and mites – that  feast on the tender plant parts and these same pests overwinter on the fruit trees. Dormant oils help control these annoying pests and are safe for use on fruit trees.

Dormant sprays or delayed dormant sprays are a generic term for an application of pesticides—including fungicides, highly refined horticultural oils and oils in combination with a pesticide– that are  applied to leafless deciduous trees during fall, winter, and early spring. All fruit and nut trees and many landscape trees and roses are susceptible to aphids, mites, scale and specific insect and disease problems affecting fruit quality and tree health

Some dormant sprays are applied to control over-wintering insects, while others are used to prevent disease infection.  While dormant sprays are commonly used on fruit trees, they can also benefit roses and other ornamental shrubs that might develop insect or fungal disease problems as the warmer weather arrives in the spring. Dormant sprays should only be used in conjunction with good garden sanitation. Be sure to rake up and dispose of all fallen leaves and debris that may harbor fungus spores and overwintering insects.

Dormant oil is a refined petroleum product formulated for fruit tree use. It has been in use for well over a century in commercial orchards, and is still regularly used today. It is classified as an insecticide, and acts by coating over-wintering insects hiding in tree trunk and limb bark with a suffocating layer of oil. Oils used at this time of year include insecticidal oils, narrow range, supreme and superior oils. Dormant disease control applications use materials such as copper, lime sulfur, Bordeaux, and synthetic fungicides.

Dormant sprays provide efficient and economical treatment for a number of over-wintering pests and diseases such as: scale, peach twig borer, aphid eggs, leaf curl, powdery mildew and shot hole. Here is a partial list for fruit trees:

• Apple and pear – dormant oil helps control scale, overwintering aphids, mite eggs and pear phyla.

• Apricot – dormant oil helps control scale, mite and aphid eggs and peach tree borer. Never use sulfur on apricots.

• Cherry – is susceptible to oozing from gummosis (Bacterial canker) and may respond to dormant sprays containing fixed copper.

• Peach and nectarine – require repeated applications of fixed copper spray to control peach leaf curl. In December or January, prune off half to two thirds of last season’s growth to stimulate new fruiting wood. Spray the ground after removing leaves and branches. Use dormant oil if scale is present.

• Plum and prune -dormant oil helps control scale and overwintering aphid and mite eggs. Apply copper for shot hole fungus. Heavy pruning may be needed to help control tree size. Spray ground after clean up.

• Nut trees- remove any nuts still hanging on the tree. Spray with dormant oil to control scale. Oil sprays also help control peach tree borers and mite eggs.

Applying dormant or delayed dormant treatments

A dormant spray may not be required every year in the backyard orchard. For some insect pests and diseases, one dormant application may be adequate with good spray coverage. For other problems, up to 3 applications may be necessary for good control. Decide if you need to apply by noting the amount of insect and disease pressure during the previous growing season. If you decide to spray always read the label and follow the directions, more is not better. Make sure you dress in protective clothing, including long pants, a long-sleeved shirt, chemical-proof gloves, and safety goggles.

Treat at the beginning of dormancy in late November and again just before the buds begin to open in February or early March. One way to remember when to consider dormant spraying is to do so around Thanksgiving, Christmas and Valentine’s Day. Once flower buds begin to open you may damage fruit and kill pollinating bees if spraying is done at this time. Therefore, it is important to spray at the proposed times before “bud break”. Spraying after pruning allows maximum coverage since there are no leaves to block the spray. A good time to spray is right after a period of rain or foggy weather but not during fog, rain or right before a freeze. Avoid spraying trees that are showing signs of drought stress.

Sprays can be applied with a pump sprayer or hose-end sprayer that is sized appropriately for the number of plants you need to spray. The sprayer should be clean, in good working order and not been used for any herbicides.  Spray the entire dormant plant taking care to saturate every branch, stem or cane as insects and the tiny dust-like spores of fungal diseases hide in the smallest nooks and crevices. Don’t use a dormant spray on any plant that has any leaves or is actively growing. Leaves, especially tender new growth, may be damaged by the spray from the impurities in the oils or the reflection of the sun off the oil.

Dormant oils generally won’t harm beneficial insects since they are applied at a time when beneficial insects aren’t present on fruit trees and have a low toxicity level to humans and mammals. Furthermore, dormant oils won’t leave harsh residue behind. It loses its ability to control pests once dried.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  ucanr.edu/sjmg

 

 

 

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Winter blooming plants to brighten the garden

Winter is a thankfully slow and sleepy season in the garden. Fallen leaves have been cleared away, lawns need less mowing, and busy gardeners can take a breather from the never-ending maintenance chores of the warm growing season.

Once the weather turns cool and cloudy, what better way to chase away the winter doldrums than to walk through your yard and see a splash of color?

This time of year, most nurseries sell favorite bedding plants such as cyclamens, pansies, and primroses, or standard winter-blooming shrubs such as camellias. But are you ready to try something new?

Rather than relying on the old standbys, think outside the box and consider planting one or more of these unique, reliable, and colorful winter-blooming perennials. There’s still time to plant these gems and take advantage of the prime fall planting season.

Hellebores

Helleborus ‘Peppermint Ice’ (Photo from Annie’s Annuals & Perennials, www.anniesannuals.com)

Commonly known as “Lenten Roses” or “Christmas Roses,” these stunning, long-lived accent plants have large, distinctive, cup- or bell-shaped flowers that face outward or nod downward. They’re not true roses, but are members of the buttercup family. The blossoms come in an interesting range of colors­­—white, cream, pink, reddish, deep purple, even chartreuse—and they’re borne on long stalks that barely rise above the foliage. Once the peak bloom period is over, the flowers persist instead of wilting, and they turn green in color. Hellebores generally need moderate to regular water and rich, well-amended soil. In our hot-summer climate, these beauties should be planted in a shady or partly shady location without afternoon sun, such as on the north or east side of a house or under a deciduous tree. (Use caution where pets or small children are present, since all parts of Hellebores are poisonous if eaten; fortunately, the horrible taste discourages consumption.) Here are a couple of interesting varieties to consider:

Helleborus orientalis. The flowers of this species vary in color and are often purple-speckled; the foliage is attractive and toothed. It’s more tolerant of transplanting than other Hellebores, and will often self sow if in its happy zone.

Helleborus x hybridus. These have been bred for a wide range of flower color and form; especially pretty is the Party Dress group, with its ruffled double flowers. These Hellebores perform better in poor soils than most others; they will even do well in clay soils as long as they’re not water-logged.

Grevilleas 

Grevillea lanigera ‘Coastal Gem’ at the Fair Oaks Horticultural Center (Photo by Kathy Ikeda)

This ancient and attractive genus of flowering plants is native to Australia. They can range in form from spreading groundcovers to mounding shrubs to towering trees. Several Grevillea species perform brilliantly in our Central Valley climate. Their flowers are uniquely shaped; they begin as tight rolls then unfurl to a slender, curved form. The brightly colored, spidery blooms are usually held in compact clusters, and they’re irresistible to hummingbirds. Grevillea leaves can be needlelike, deeply cut and lacy, or stiff and oak-like. Some species bloom in winter; others have their prime bloom season in spring and fall, so choose your plant carefully. Most Grevilleas need well-drained soils, and are best planted in organically amended soil or at the top of a slope; some species are tolerant of clay soils.

Grevillea lanigera ‘Coastal Gem’ (Woolly Grevillea). An excellent, low-growing, compact shrub with small fuzzy bluish green rosemary-like foliage and beautiful bicolor flowers that transition from deep rose to cream. It often flowers from December through spring, and thrives in full sun. It can also tolerate periods of wet soil.

Grevillea rosemarinifolia (Rosemary Grevillea). This large shrub has reddish-pink and cream flowers, and its leaves look like those of its namesake rosemary. Although it bears blooms most heavily fall and winter, it blooms sporadically throughout the year. It’s very adaptable to heat and dry conditions.

Manzanitas

These California native shrubs are known for their distinctive reddish bark, stiff glossy leaves, and profuse winter blooms. The clusters of tiny urn-shaped blossoms are favored by hummingbirds, bees, and other beneficial insects. Manzanitas generally prefer poor (rocky or sandy) soils to rich or heavy ones, and they must have good drainage and air circulation. One of the best for our Central Valley growing conditions is:

Arctostaphylos densiflora ‘Howard McMinn’ (Vine Hill Manzanita). This species is covered with delicate pink blossoms from late winter to early spring. It’s an ideal large shrub for our area, since it is accepting of a wide variety of soils, needs very little summer water, and handles pruning better than other manzanitas.

Fuchsia-Flowering Gooseberry

Fuchsia flowering gooseberry at the UC Berkeley Botanical Garden (Photo by Kathy Ikeda)

 

 

 

 

 

 

 

 

 

 

 

 

This showy California native gooseberry (Ribes speciosum) bears a profusion of pendulant scarlet-red flowers in late winter to early spring. The spiky round fruits that follow turn from mellow green to red-orange. The flowers attract hummingbirds, and the spiky fruits are attractive to a variety of birds. The plant itself has an attractive form, with long arching stems covered with small, lobed, bright green leaves. But beware: it’s also very thorny, and makes a good deterrent plant! This gooseberry requires partial shade and well-drained soil, and although it needs no summer water once established, it should be given some hot season irrigation to avoid summer dormancy and keep the foliage green and on the plant throughout the year.

For gardening-related questions, call the UC Master Gardener office at 209-953-6112, or use our website.

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Good soil is the gardener’s best asset.

Gardening is not just about plants, landscapes, flowers and vegetables. There is always the basis of a great garden—the soil to consider. I always recommend to people who want to get back to the land or want to commit to serious gardening to check out the soil before they buy property. That said, I recently bought property

Black adobe clay soil makes these hard to break clods when soil is worked too dry or too wet.

without following my own advice. I got black adobe clay which is the soil I had for my first home in Stockton purchased in 1968. Had I known that was what I was buying, I might have had a few second thoughts.

Black adobe is a heavy black clay soil common to North Stockton. It is rich and fertile, but it is also tillable at noon on one day of the year, so some say. The rest of the year it is either too dry and unbreakable or too muddy and gummy to deal with. Clay soils have relatively low pore space compared to sand soils, hence they drain very slowly and if compacted, drainage is much reduced. However, I have dealt with black adobe before and can deal with it again. One way around it is to use raised beds filled with other soil as I mentioned in last week’s article and/or add lots of compost to help

Clay soils crack open in the dry season.

loosen it up.

Why are clay soils rich and fertile?  Soil can be clay, silt or sand particles or some combination of these particles. The combinations are loams and named according to the dominant particle type and thus we have: sandy loams, clay loams and silt loams. Loams are considered more ideal because they are easier to till and they drain faster than pure clay soils and less rapidly than pure sand soils.

Clay particles are the smallest of the three types and are bound end to end and side to side in extensive planes in a sandwich like matrix held together by electrochemical charges. A clay particle is about 250 times smaller than a medium grain of sand to give you an idea of how different these soils are.

Individual clay particles are negatively charged so they have the capacity to attract positively charged elements (cations) such as ammonium, potassium, calcium, magnesium and other trace elements that are necessary for plant growth. Sand, on the other hand, has single uncharged particles that do not attract cations and hence it is not a fertile soil. It is also why fertilizer leaches more readily out of sandy soil as there are no electrochemical charges to hold the cations.

While soil structure, the way soil particles are assembled as aggregates, is an inherent property of the soil type that cannot be changed, it can be improved. Clay soils consolidate over time into tight and sticky stuff. To achieve a more granular looser crumbly soil with ease of tilth, the addition of compost and organic matter is necessary. Cover crops which send roots deep into the soil and also add organic matter when tilled in also helpful. For more information on improving clay soils for gardens see: http://vric.ucdavis.edu/pdf/soil_managingclay.pdf.

One recommendation is to use a spading fork instead of a shovel to till clay soils and not to till when the soil is too moist, which will result in large clods and greater compaction.  Application of gypsum may help break up clay soils. It should be applied at the rate of 1 pound per 5 square feet. However, the benefits obtained, if any, will likely be temporary, because irrigation water will gradually dissolve the gypsum out of the soil. Applying lots of organic matter such as manures, compost and green cover crops will be a more long term fix.

Lawns in clay soil may suffer from shallow roots and compaction of the soil which may retard water penetration. Aeration of the lawn with an aerifier that removes soil core plugs 3 to 4 inches deep is a good way to improve the drainage and getting air to the turf roots. Fill the plug holes with fine compost or other fine organic material after aeration.

Soil is more than the mineral particles. Soil is not dirt; that’s the stuff you pick up with a vacuum cleaner. Soil is a living substance with an entire ecosystem of bacteria, fungi, protozoans and invertebrates that include nematodes, earthworms. These living parts of the soil have symbiotic relationships with plants that help keep them nourished and disease free as well as keeping the soil healthy. So feed and treat your soil well as it is a living thing that makes your garden grow and shine.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website:  http://sjmastergardeners.ucanr.edu/CONTACT_US/

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    Lee Miller

    Lee Miller is a University of Delaware graduate and retired fisheries biologist, he gardens on 10 acres and makes wine each year with the help of a cadre of friends. However, his first love is gardening and he grows various fruit trees, heirloom ... Read Full

    Marcy Sousa

    Marcy Sousa is the San Joaquin County UC Master Gardener Program Coordinator. She is a Stockton native and enjoys teaching others about gardening. She has her bachelors from Stanislaus State in Permaculture. She has been with the program since 2007. Read Full

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    Nadia Zane is a UC Master Gardener, a landscape designer and Stockton native. She has a fondness for California native plants and sustainable landscaping, which she utilizes in her work for Native Beauty Garden Design. She is a member of the CA ... Read Full
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