For the love of lavender

Lavender is one of the most beloved and oft-used plants in the history of human civilization, and its name has become synonymous with a light shade of purple. Nowadays, its delicate foliage and beautiful, distinctively scented flowers make it a garden favorite.

The genus name of lavenders, Lavandula, means “to wash” in Greek. Known for their antiseptic and medicinal properties, lavender extracts and products have long been used as disinfectants, fresheners, and laundry and bath additives. Lavender essential oil is commonly used in aromatherapy (the practice of healing the body and soothing the mind with herbal extracts).

Lavenders are native to areas around the Mediterranean Sea (southern Europe, northern Africa) and southwest Asia. They’re perennial plants adapted to warm, dry summers, winter precipitation, and sunny exposures. This makes them ideal for our inland California climate. Once established, their water requirements are low to minimal, and they’re well suited for water-thrifty landscapes. They’re also outstanding performers in mixed perennial beds and herb gardens.

Beneficial pollinators such as honeybees and butterflies find lavender flowers irresistible. On the other hand, the aromatic chemical compounds in lavender leaves act as natural pest repellants. Lavender plants are rarely bothered by harmful insects, and snails and deer avoid them.

Soil type is an important consideration when growing lavenders. They absolutely require well-drained soil, and will suffer in soggy soils or heavy clay. Amend garden beds with organic matter or fine gravel, or locate plants on a raised berm. Here are a few lavenders to consider planting in your garden:

A drift of ‘Hidcote’ English lavender in full bloom. (Kathy Ikeda)

English lavender (L. angustifolia).This is the iconic, sweetly-scented lavender plant most commonly used in sachets, perfumes, and soaps, or to lend subtle flavor to drinks and foods. It has dense, narrow green leaves and delicate flowers that grow in whorls at the end of each stem. Some excellent landscape varieties include ‘Munstead’ (a heat-tolerant dwarf with purple flowers), ‘Hidcote’ (a compact plant with vivid blue-purple flowers), and ‘Thumbelina Leigh’ (a tidy dwarf with intensely scented flowers). There are also several late-blooming, commercially valuable English lavender hybrids (Lavandins); two of the best known are ‘Grosso’ and ‘Provence.’

Honeybee visiting a Spanish lavender flowerhead (Kathy Ikeda)

Spanish lavender (L. stoechas). Spanish lavender flowerheads resemble small pineapples; each has a dense, oblong cluster of small flowers topped with several petal-like bracts. This species blooms heavily in early spring, then more lightly in summer. Its foliage is grayish-green; the flowers vary in color depending on the variety.

French lavender (L. dentata). Despite its common name, this species originated in Spain.  The specific epithet “dentata” (meaning toothed) was given to this plant for its leaves, which have serrated, tooth-like edges. Its pale purple flowers resemble Spanish lavender, but it’s longer-blooming.

Goodwin Creek lavender (L. ‘Goodwin Creek Grey’). This is a vigorous, long-lived lavender with stunning silver-grey foliage. It performs admirably in hot-summer areas, and blooms almost year-round in mild weather. It bears numerous spikes of violet flowers with a spicy-sweet scent.

Fernleaf or Egyptian lavender (L. multifida). This unusual variety has soft, finely-divided, grayish-green foliage and distinctive, three-pronged flowerheads with purplish-blue blooms. It’s long-blooming and very tolerant of heat and dry conditions.

Like all members of the mint family (Lamiaceae), lavenders have square stems. Try rolling a lavender stem between your thumb and index finger; the flattened sides are very noticeable.

If you enjoy botanical handicrafts, try making sweetly fragrant, decoratively woven lavender wands. They’re relatively simple to create, and they retain their scent for years. English lavenders are best suited for this, but other long-stemmed lavenders can be used if you prefer a spicier, less perfumy aroma. (Spanish and French lavender will not work well; the flowerheads are too bulky.)

For a special outing, visit one of the several lavender farms in northern California. Pageo Lavender Farm in Turlock is the closest, with peak bloom in June. Bluestone Meadows in Placerville grows 24 different cultivars of English and French lavender; their annual festival will be held on June 16-17. Your senses will be well-rewarded!

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

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Plan ahead for upcoming garden events

This spring season promises to be a glorious time to enjoy the outdoors. Drought-stressed plants have been rejuvenated, and their blooms should be spectacular. Yet despite last winter’s unusual deluge of rain, water conservation should continue to be a priority for all Californians, both in the home and in the garden.

We’re fortunate to have many beautiful, well-designed, water-thrifty landscapes within easy driving distance, and they provide great opportunities for weekend outings. The next few months will be an ideal time to visit one of the public gardens or garden-related events in our area, including:

Spring Open Garden Day
Saturday, April 22 from 9:00 a.m. to noon
Robert J. Cabral Agricultural Center
2101 E. Earhart Ave., Stockton

This event showcases the UCCE Learning Landscape, a demonstration garden created and maintained by the San Joaquin County UC Master Gardeners. Save a spot on your calendar now, and watch for a soon-to-appear article with more details.


Gardens Gone Native
Saturday, April 8 from 9:30 a.m. to 4:00 p.m.
Various locations in the greater Sacramento area

This is a free annual event organized by the Sacramento Valley Chapter of the California Native Plant Society (CNPS). This year’s self-guided tour features 28 private gardens wholly or partially landscaped with California native plants, with a mix of professional and homeowner-created designs. Garden hosts will be available at each location to answer questions, and detailed plant lists are provided.

The sites on this tour are within Sacramento, Yolo, and Placer counties, with eleven gardens in the nearby cities of Sacramento and Elk Grove. For more information and to register, visit and select on “Events and Field Trips.” Maps and garden descriptions are provided upon registration.

Hummingbird sage and stepping stones at the 2016 Gardens Gone Native tour (Kathy Ikeda)

Mixed California native and Mediterranean plants in a garden on the 2016 Gardens Gone Native tour (Kathy Ikeda)














Bringing Back the Natives Garden Tour
Saturday, May 7 from 10:00 a.m. to 5:00 p.m.
Various locations in the East Bay area

This is another free, self-guided tour, although donations are welcome to ensure that tours can be offered in the future. This year the event showcases 40 native plant gardens in Alameda and Contra Costa Counties, including some newly planted ones and others that have been thriving for years or even decades. A two-day plant sale featuring several native plant nurseries is also a part of this event.

Locations for this tour are divided into two categories: Bayside Cities and Inland Cities. If you want inspiration for your Central Valley garden, visit sites in the latter category, since the climate in inland areas most closely matches our own.

To register for this tour, view a tour flyer, or access other information (2017 garden listings, photographs from prior tours, plant lists and descriptions, and more), visit All registrants receive a detailed garden guide (free in PDF format, $10 in print). Access to the gardens will only be granted with the ticket included in the guide.


Sculpture in the Garden
Tuesdays-Sundays, June 17-August 13 from 10:00 a.m. to 4:00 p.m.
The Ruth Bancroft Garden
1552 Bancroft Road, Walnut Creek

The Ruth Bancroft Garden is a non-profit dry garden planted with cacti, succulents and other water-thrifty plants from around the globe. This annual exhibit combines the best of both worlds: stunning plants interspersed with bold and innovative 3-dimensional artwork in a 3.5 acre outdoor setting. Garden pathways are unpaved but handicapped accessible. Garden admission is $10 for adults, $8 for students and seniors, and free for members.

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

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Try Water-Wise Plants This Spring

Douglas Iris 'Canyon Snow' is a lovely addition to the dry shade garden

The abundant rains we received this past winter have our reservoirs feeling less empty, but any long-term California resident knows how quickly this can change. With spring weather comes the opportunity to make changes in the garden that reflect our need to conserve this precious resource.

Although everyone’s garden is unique, there are plants of all sizes, shapes, and colors to choose from. The following plants are some of my favorites, being easy on your water budget, easy to care for, and native to California (except where noted).

If you have a large garden, consider planting a Valley Oak tree (Quercus lobata). They are invaluable to the ecosystem, offering food, shelter, and reproductive habitat for wildlife. Their spreading, gnarled branches are an icon of the Central Valley, and too many have been lost due to extreme drought (they do need some water in the summer, contrary to popular belief).

For urbanites with small gardens, try medium-sized trees. Ceanothus ‘Ray Hartman’ is a native evergreen tree with dark green leaves and clusters of purple, pollen-rich flowers in late winter. Pineapple Guava (Acca sellowiana), native to South America, has bright, silvery-green foliage and beautiful pink and red flowers in spring that attract hummingbirds. A lesser known but easy to grow tree is the Mountain Mahogany (Cercocarpus betuloides), another native plant with evergreen, scallop-shaped leaves and whimsical, feathery plumes attached to the seeds.

Large shrubs (and trees) provide permanent structure to your landscape and habitat for wildlife. Bush Anemone, a California native plant with large, white flowers in late spring and dark green foliage. is easy to care for and prefers part sun. Another tough plant with a wide range of light tolerance is Coffeeberry ‘Mound San Bruno’ (Frangula californica). Like the Bush Anemone, it has dark green foliage but without showy flowers. If given a little water in summer, it will produce berries in winter that change color from white to dark purple as they mature. These are a favorite for birds, but could potentially stain a sidewalk so plant it away from paths.

With all the little “cutie-pie” perennials out there; it’s difficult to narrow down the choices! Rosy Buckwheat (Eriogonum grande v. rubescens) is low-growing with evergreen, oval-shaped leaves, and flower stalks topped by cluster of pink blossoms. A favorite of pollinators, they grow in full sun or afternoon shade. Douglas Iris ‘Canyon Snow’ is a variety of evergreen iris with snowy-white blooms in spring. They prefer part sun and can be divided every three-four years like other members of the iris family. Another favorite is Dudleya, a group of native succulents (plants that store water in their foliage and stems, like Hens and Chicks). Dudleyas have silvery or silvery-green leaves and stalks of brilliant orangey-red or yellow flowers for hummingbirds. Dudleya species such as Large Chalk Dudleya (Dudleya brittonii) form large rosettes, making them perfoct for a focal point. They also make great container plants.

Some of the plants listed above can be found at local nurseries with a good selection of  California natives. These and many more water-wise plants can also be found at the UC Davis Arboretum Teaching Nursery during their spring (and fall) plant sales. There are two more plant sales this spring, on April 8th and 29th from 9am-1pm. For more information, go to their website at <>.

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:

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Managing Weeds Without Herbicides

Field Bindweed requires persistent management if allowed to become established

Weeds. What would spring be without them? For some, weed-pulling is calming and meditative. For others, it is a loathsome task leading to feelings of anger, frustration, and orneriness. How can we maintain a weed-free garden and our mental health?

Like illness in the human body, weeds are often a sign that something has gone awry in the garden’s ecosystem. Herbicides can be tempting with their promises to be a “cure-all” for your weedy woes. Unfortunately, “weed-free gardens” are impossible, at least in the long term, and launching a chemical assault introduces toxins into your immediate surroundings. Instead, try turning those unwanted, irritating plants into an opportunity to learn about why they happen in the first place, and what you can do about it.

There are myriad factors leading to weeds, and many are caused by humans. Not what you wanted to hear? We would certainly prefer to blame nature, but the fact is, humans have transferred plants (and animals) around the globe for centuries, both intentionally and unintentionally. Seeds hitching a ride on boots or animal fodder, for example, were dropped off wherever people went. Upon reaching their destination, seeds either perish because the climate is unsuitable, or thrive because the climate is great and their natural enemies stayed home.

Although weeds settle in quickly when they find favorable conditions, there are steps you can take to reduce their numbers. The easiest, and most beneficial practice is to lay down a 3”-4” layer of mulch around your plants, preferably organic (e.g. bark). This prevents weeds from germinating in the first place and protects your soil (and desired plants) from heat and drought.

There will always be some weeds that manage to peek through mulch, so try to pull them before they go to seed and make little ones. Perennial weeds (those living three or more years), such as field bindweed, form extensive root systems that take hold quickly unless yanked out the minute their fearsome foliage appears. If you inherit a thick, hearty patch of established weeds, you will likely need more specific control strategies. The University of California Integrated Pest Management website is a good place to start: <>

To prevent existing seeds from germinating, avoid tilling the soil, which brings them to the surface. Tilling is also damaging to soil health and should not be practiced on a regular basis. For large areas that are bare for part of the year, try growing cover crops, which are plants grown to benefit soil health and provide a living mulch that blocks weeds from growing. This is a great idea for dormant vegetable gardens in winter, when rains can provide the irrigation. More information on cover crops can be found at <>

Many weeds start out their lives in nurseries as adorable little bundles of joy in a 4” container. After the initial fun, the “terrible twos” start up, and that precious purple morning glory vine is wreaking havoc on your neighbor’s fence three doors down, and that wisteria vine lifts your house off its foundations (true story, by the way). Be aware of what you are planting and whether you have the commitment for long-term management. Even though many nurseries have stopped growing some of the worst offendors, check out the California Invasive Plant Council’s website at <> to find out which species have the potential to escape into the wild and cause trouble in natural habitats.

Weeds are ubiquitous, and managing them is an ongoing task. If emotional trauma persists, remember that weeds were born the day a human looked at a poor, innocent plant and decided it needed to go away. They are illiterate organisms who have never read a gardening book, and have zero control over where their progeny lands. Avoiding the toxic effects of herbicides means creating an unfavorable environment for weeds, and, hopefully, less weed-pulling for you.

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:

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Citrus thoughts for spring

It is time to consider caring for your citrus or planting some if you have none and want to enjoy picking your own ripe tangerines, oranges, lemons, limes, pummelos, and grapefruit. There are lots of citrus suitable for planting in San Joaquin County. One of the best to plant is a dwarf, Improved Meyer lemon. It is a highly productive variety that is somewhat freeze resistant and will keep you in lemons for a few months annually. Meyer lemons are a little sweeter than other lemons.  I have one that is about 40 years old and still going strong and very productive. It can be planted in containers as well as in the ground, but if you want to give it room with less fuss—plant it in the ground. Folks in parts of the country where it freezes can grow them in containers so they can be moved to a warm spot for the winter.

If you want a more tart lemon, I can recommend ‘Lisbon’ which is less likely to be damaged by freezing temperatures than the ‘Eureka’ variety. The Lisbon or Eureka lemon both require more diligent pruning than the Meyer. They tend to grow more vigorously, with long straggly branches. Hence, they need pruning to keep them stubby and supportive of the fruit that they abundantly produce.

When to prune citrus, is a question often asked of Master Gardeners. The ideal time is in the spring after any frost damage can be observed and removed and before new growth occurs or summer heat sets in. Spring is also the best time to purchase and plant new citrus trees. Pruning out water sprouts (gourmands) may improve yields because more energy can go toward fruit production. Water sprouts will not produce fruit. Pruning can improve fruit quality through increasing light in the canopy. In older trees, reducing tree height facilitates harvesting and reduces risk of injury from ladders. The best approach is to plant dwarf trees and avoid heights where possible. Skirt pruning facilitates weeding, mulch additions, and other cultural practices, as well as reducing risk of soil borne pathogens affecting the fruit. Pruning may reduce insect and disease pest problems.

A mature Improved Meyer lemon that needs to be skirt pruned to provide more clearance underneath the tree.

If you have older trees, say greater than 40 years old, it is good to disinfect pruners after pruning and before pruning younger trees. Use of disease free budwood and rootstock in more recent years has reduced the incidence of these diseases. Older trees are more likely to harbor viruses and they may be spread by the pruning tools if not disinfected. A 15 percent bleach solution or Lysol can be used to disinfect pruners.

I had a Valencia orange that was over 50 years old and it developed Psorosis, a virus disease causing shelling of bark on the scion caused by a virus. It was also common on old trees before it was eliminated in nursery stock. My Valencia, which produced lots of oranges for several years, finally declined over time and had to be removed. It will take my young Valencia many years to become as productive as that old tree.

As with any tree pruning it is important not to damage or remove the branch collar which produces the tissues which heal the wound. The branch collar is the area around the base of a large branch, often visible as a ridge or wrinkled bark around the branch. It contains a narrow band of cells known as the “branch defense zone” which activate the growth of the callus tissue that grows over the pruning cut. Citrus bark is also thin and easily damaged so care should be taken not to scar the bark.

In order to shape a young tree, downward growing shoots should be pruned to allow upward growing buds to become dominant. Cutting the shoot just above an axillary bud (the bud in the angle between the leaf and the stem) pointing upward will redirect growth upward. This will help shape the tree for future production.

Beware of any shoots that are thorny and originate below the scion wood on the rootstock. These shoots below the bud union should be removed as soon as they appear.  For trees on Trifoliate rootstocks (Poncirus trifoliata), the thorns from the rootstock are very obvious and hazardous to your skin.

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:

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Some of the good fungus among our plants

On January 13 National Public Radio presented a segment on forests investigations by Suzanne Simard, a forestry ecologist, who worked out how trees in the forest can communicate and share resources by use of underground connections via fungi mycelium. It was very fascinating and the presentation is on TED  One has to wonder if such communications and sharing of resources happen outside of forests, but we do know that fungus and plants go together.

What is mycelium one might ask? Mycelium is the vegetative part of a fungus or fungus-like bacterial colony consisting of a mass of branching, thread-like hyphae. These vegetative components of fungi are less conspicuous than the reproductive fruiting stages that we recognize as mushrooms, but the mycelium often forms symbiotic relationships with the plants in our gardens. They also are important in breaking down material in ecosystems and in our compost piles. It can be seen in the compost pile as light grey threads. Mycelium is good at breaking down lignin, the woody parts of plants. In compost piles they operate best at temperatures less than 120 ºF. They are also good at breaking down and detoxifying hydrocarbons often found in industrial wastes such as oil and pesticides.

The mycelium, when in a symbiotic plant relationship, is termed mycorrhizae. The term comes from the Greek word ‘mykos’ meaning fungi and ‘riz’ referring to root and hence describes the symbiotic relationship between a fungus and the root of a vascular plant. There are actually two kinds of relationships; endomycorrhizae actually invade the plant root cells whereas ectomycorrhizae form a sheath around the root, but do not invade root tissues. Endomycorrhizae are also referred to in the literature as arbuscular mycorrhizae.

The fungi benefits from sugars that the plant produces and the plant benefits because the fungi shares phosphate, nitrogen, iron, copper and other minerals with the plant. The host plant may donate between 4 and 20% of its photosynthetically fixed carbon to the mycorrhizal fungus. Mycorrhizae also help increase the surface area of the plant root system because hyphae can spread beyond the nutrient depletion zone. The benefits of the mycorrhizae are most evident on poor soils where plants are nutrient challenged. Mycorrhizae also help protect plants from root pathogens and help plants withstand drought.

Fossil records indicate that these symbiotic relationships have been around for 400 to 450 millions years and these fungi are widespread in our environment. They likely helped plants adapt to a terrestrial existence as they colonized the earth. Approximately 80 % of all known land plant species form mycorrhizal interactions with these ubiquitous soil fungi. However, there can be situations where the mycorrhizae are not present because of construction or other soil disturbances. This is where entrepreneurs have come to the rescue by providing a variety of mycorrhizae for use in compost, greenhouses, agriculture, turf and other situations.

In doing research for this article, I came across a study made by a master gardener in another county were the MG had planted a variety of plants in the same soil mixture but with and without mycorrhizae. The test of the difference caused by the mycorrhizae was to measure the height of the plants. It actually did show differences, but they were small except for the Cardoon which with mycorrhizae was twice as tall as the one without the mycorrhizae. I think the study would have been more successful if they had used poorer soil for growing medium instead of the rich medium they used. This would perhaps have enhanced the effect the mycorrhizae. It is also unknown if they used the best mycorrhizae for the plants grown because there are lots of species.

However I have seen other studies where the plant size was markedly greater when mycorrhizae were present versus plants were it was absent. For example, potatoes grown with mycorrhizae present yielded 33 percent more by weight than potatoes grown without mycorrhizae. Cabbages and its relatives are one of the few plants that don’t have mycorrhizae helping them grow. For more information on kinds of mycorrhizae see: It is good to know that the fungus among us is not all bad and in fact vital to good gardening success.

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:

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What’s Old is New Again

A very basic concept has sparked an exciting revolution with this generation, but it is far from new. Upcycling is the act of taking something no longer in use and giving it a second life and new function. Some of the best examples of modern-day upcycling come from the 1930s-40s when families had very little economic or material resources. In this age of thrift, they reused almost everything, repurposing items over and over until they were no longer useful: Feed sacks became dresses or old doors became the new dining room table.

Thrift is still a trend today and a big reason some people upcycle. Others enjoy the artistic aesthetic. One of the biggest reasons for the rebirth of upcycling is the positive impact on the environment. Items destined for the dump are rescued and remade into something useful.

Many garden upcycling ideas start with items around the house and a need for something. So, before you throw away or recycle broken or used items, give them a second look and ask yourself if they can be used in the garden. A quick search on the internet under “repurposing or upcycling in the garden” will give you all the inspiration you will need to get started. We aren’t all artists, but with some elbow grease and a little creativity, even the novice can fashion some fun and quirky statements for the landscape.

Here are some of my favorites to help get you started!

  • One of the first projects to come to mind are upcycled garden containers like an old bird cage with a spill of charming succulents in the bottom. Paint old tires in vibrant hues, stack them and fill with dirt. Use colanders to make hanging baskets or decorate an old dresser and plant in its drawers. An old chandelier can be spruced up with some paint and makes a great hanging flower planter.  Whimsical items take on even more charm when plants are installed in them. Children’s rain boots, rusty tool boxes, old tins, teapots, glassware, and more provide interesting planting options.
  • Install an old mailbox onto a fencepost near your garden, and use it to keep gloves, tools, seed packets, and other necessities nearby and safe from the elements.
  • Milk jugs are amazing garden tools! They can be used as cloches, seed starters, scoops, waterers, dusters, upside-down vegetable planters, and more!
  • Yogurt containers, egg cartons, and toilet paper rolls cut in half make perfect containers for holding soil and starting small plants from seeds. Make sure to poke a few holes in the bottom of anything that is solid to allow water to drain.
  • Use plastic mesh baskets from cherry tomatoes or strawberries to protect newly-sprouted seedlings such as corn, cucumber, melons, and squash from birds.  By the time the seedlings are tall enough to reach through the tops of the baskets, they are no longer as tender and detectible as the birds prefer.
  • Save sets of jars for sorting and storing seeds you’ve collected.  Use the same type of jar for each type of seed for quick sorting.  Choose the jar size to match the quantity of seeds you have.  Place them together on a shelf for quick, at-a-glance recognition and easy retrieval.
  • While some plants require lots of room to be happy, succulents actually do better in small containers or planted close together. Colorful food cans make great homes for succulents!
  • Don’t throw out that chair with the broken seat! Turn it into a pretty planter for petunias and other flowers.
  • Planting veggies and need some plant labels? You can paint old kitchen spoon vibrant colors and add your sprouting seedling name. Old mini blind vanes or pained rocks work well too! If you have some wine corks lying around, you can stick them on a bamboo skewer and write the name on the cork for a unique label.
  • Turn an old, broken bike into a cool planter.  Paint it bright colors, install a planter or basket at the handle bars and park it amongst a wildflower garden.
  • Decorative garden balls are an inexpensive alternative to the classic gazing ball. Take an old bowling ball or mason jar, add some paint and glue on some flat marbles (glass gems), pennies, or old costume jewelry to create a unique garden decoration.

With upcycling, the possibilities are limited only to the materials you already have on hand and your creativity. Dig around your basement or garage or scour yard sales to find objects that appeal to you. Then get out the paint, super glue, twine, glue gun and any other decorating tools you need and go to town. Upcycling in the garden can be a fun, family project that let’s everyone put a special touch on your outdoor spaces while making a positive impact on the environment.

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




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Inspecting Trees for Hazards

Storm damaged trees are something many homeowners will have to deal with at some point. This last storm brought with it some pretty powerful winds and with that many downed fences and trees. For some, it may be too late to inspect trees for potential hazards but hopefully for many of you, this last storm spared trees planted around your home and neighborhood.

Although some tree failures are not predictable and cannot be prevented, many failures can be prevented. By inspecting trees for common structural defects, many potential failures can be corrected before they cause damage or injury. It is best to make inspections before stormy weather and immediately afterward.

You should inspect healthy and unhealthy trees on a regular basis. Large trees have a greater hazard potential than small trees and should be inspected more frequently and in greater detail. Always make your inspections from the ground, do not climb the tree or use a ladder to improve your viewing perspective. If you suspect a hazardous condition, immediately contact your utility company and consult an arborist who has the equipment and training to conduct the inspection safely. If you determine that a tree is a potential hazard, keep people, pets, and vehicles out of the area until the hazardous condition has been corrected.

Thoroughly inspect the tree for the following defects:

Lean: Determine whether the vertical axis of the tree has recently changed and check the ground around the base of the tree for uplift or exposed roots. If the tree was vertical but has moved from the vertical position, it is called a leaner. These are trees that are in the process of falling and could fall completely at any time and require immediate attention.

Multiple trunks: Some trees develop more than one trunk, which are often weakly attached and prone to splitting apart— especially those with narrow angles of attachment. This condition is a concern in large trees. Inspect the point where the trunks meet.

Weakly attached branches: Inspect large branches (greater than 3 inches) at the point where they attach to the trunk. Trees with many branches arising from the same point on the trunk are weak and potentially hazardous. If one branch breaks, the others are more likely to fail.

Cavities, large decay pockets, and other evidence of decay: Inspect the trunk and large branches for cavities or large decay pockets. If you find cavities or decay at a point where loads are great (where branches meet or at the base of the trunk), they are a concern. If a cavity or decay pocket is especially large and is at a key structural location, the tree is more likely to fail.

Mushrooms and conks growing on the bark of trees or on exposed roots indicate root rot or wood decay. As the decay progresses, the wood is weakened and failure is more likely.

It is very important to have your tree inspected by an arborist if you find cavities or decay. Tree size and weight distribution should be considered when deciding if the tree is a hazard. Do not attempt to clean out or seal a cavity or decay pocket—you may be doing more harm than good.

Trunk and branch cracks: Inspect the trunk and large branches for cracks. If a crack is found, determine if it extends into the wood or is confined to the bark. Insert a pencil or other object into the crack and measure its depth. Look into the crack to see if you can tell the thickness of the bark and whether the crack extends into the wood.

Cracks confined to the bark are not usually a problem, but there is reason for concern when the crack extends into the wood. Deep cracks indicate that a separation of the wood within a trunk or branch has occurred and the tree has become structurally weakened. If you find a crack, it is best to have it inspected by an arborist.

Hanging or broken branches (hangers): Hangers are branches that are broken but have not fallen from the tree. They may still be partially attached or completely separated and lodged in the canopy. Inspect for branches that are hanging down from a break point and for branches that have broken off completely and are resting on other branches. Hangers should be removed as soon as possible.

Dead branches (deadwood): Branches that have died will eventually fall off and can cause damage when they fall. Inspect trees that lose their leaves in winter when they are in full-leaf (late spring through early fall). Evergreen trees can be inspected for deadwood at any time. If you find deadwood, plan to have it removed. This does not have to be done immediately, but should not be ignored

Obtaining professional advice and services: The best assurance of getting quality advice or tree work is by hiring an arborist certified by the International Society of Arboriculture (ISA) or a consulting arborist who is a member of the American Society of Consulting Arborists (ASCA). Certification does not guarantee quality performance, it is only a means of helping you select an arborist who has a demonstrated level of knowledge and technical proficiency. You should verify that your arborist is insured and check his or her references. When you call for service, the arborist will come out and assess the storm damage to your trees and explain the best way to repair the tree if it is salvageable.

When Tree Damage Repair Is Not an Option: Trees are beautiful, valuable assets to a property and in most cases an arborist will exhaust all other options before deciding that a tree must be cut down. Unfortunately, some storm damaged trees are simply beyond repair, and complete removal is the only safe course of action.

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

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Fundamental facts about fertilizers

Spring is almost upon us, and with the season comes a rush of new plant growth and the urge to spend time in our gardens. Although fertilizer might seem a dry topic, give it some thought before you visit your favorite nursery.

Fertilizing plants is often equated with “feeding” them, but plants produce their own food through photosynthesis, using the sun’s energy to convert carbon dioxide and water to sugars and oxygen. Fertilizers do, however, provide plants with essential nutrients for cell development, function, and growth.

The basic purpose of fertilizers is to replace soil nutrients that deplete over time. Soil composition and pH have a direct effect on what nutrients can be absorbed by plants and how efficiently, so it’s wise to do a basic soil test before choosing or using a fertilizer to remedy any apparent nutrient deficiencies.

Fertilizers come in two basic types: organic (those derived from natural sources, including plant compost, animal manure, fish emulsion, and bone meal) and inorganic (composed of synthetic chemicals). Organic fertilizers have many benefits: they release nutrients over a long period; they improve the structure and water-holding capacity of soil; and they have a complex profile of macro- and micronutrients. The downside is that they’re more expensive and can vary in content or quality. Inorganic fertilizers release nutrients quickly, are consistent in composition, and are less expensive, but they don’t improve soil quality or contain as many nutrients.

Fertilizer bag with N-P-K ratio, showing each nutrient in its usual chemical form

Every fertilizer label shows something called the “N-P-K” ratio, which indicates the percentage by volume of nitrogen (N), phosphorus (P), and potassium (K). A “balanced” fertilizer has equal amounts of each of these three plant macronutrients; for example, a product labeled 16-16-16 has 16% N, 16% P, 16% K, and 52% other ingredients. A “complete” fertilizer contains all three major nutrients; an “incomplete” fertilizer has only one or two of them.

You might think, “If I use more fertilizer than recommended, my plants will grow even better.” No! Many serious problems can result from overuse of fertilizers. Too much fertilizer can burn plant roots and foliage; surplus nitrogen can leach into and pollute water; and excess nutrients can over-stimulate plant growth, leading to an unnecessary cycle of frequent pruning and stressed, disease-susceptible plants. Fertilizers should always be applied according to the instructions.

It’s also tempting to try shortcuts, and rationalize, “One kind of fertilizer will be fine for all my plants.” Wrong! Plants have unique nutrient requirements, and different fertilizers are formulated for different purposes. For example, many plants native to Australia can be harmed or killed by phosphorus-containing fertilizers, while other plants need phosphorus to thrive. A fertilizer intended for citrus trees is different from that designed for acid-loving azaleas and camellias… and so on.

Timing is another key consideration: season, rainfall, planting dates, and other factors are important in determining the right time to fertilize. If deciding when to fertilize shrubs and trees, their age, maturity, and species should be considered. Lawns are still another matter, and homeowners tend to apply fertilizer on lawns unnecessarily and wastefully.

An effective alternative to commercial lawn fertilizers is the easy practice of “grasscycling.” Grass clippings become natural fertilizer when they’re allowed to remain in place after mowing – they decompose and return nutrients to the soil. Grasscycling is often thought of as a relatively new sustainable practice, but its benefits have been known for many decades. I recently stumbled across a 1924 article from a Midwestern newspaper that cited this advice from the U.S. Department of Agriculture: “Cuttings should begin early with the lawn mower set as high as possible and should be repeated frequently. The clippings should all remain upon the lawn. The more of these clippings that can be retained about the roots of the grass the better the chances for a good lawn.” Nowadays, lawnmowers can be fitted with special mulching blades to make the process more efficient and the clipping size small.

By now, it should be clear that fertilizing is a very complex topic with far more detail than can be covered here. Before you fertilize, make sure that you—or those you hire to care for your garden—fully understand the specific goal of fertilizing; the product that will best meet that goal; and the proper rate, method, and timing for applying the chosen fertilizer.

Two excellent online resources are “A Gardener’s Guide to Fertilizing Trees and Shrubs” (NC State University) and “The UC Guide to Healthy Lawns” (UC IPM). You can also consult the California Master Gardener Handbook (Chapter 3 – Soil and Fertilizer Management) for in-depth guidance.

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


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Getting the dirt on earthworms

Earthworms. They’re so small and seemingly insignificant that we hardly give them a second thought.

These squirmy denizens of the dirt usually go about their lives unseen—they’re revealed to us only when upturned in a shovelful of soil or when stranded on pavement after a drenching rain. (Worms crawl out of the ground during heavy storms because they breathe air through their skin and can drown if the soil is saturated with water.)

Even though they can evoke a squeamish response, earthworms are good for the garden. They burrow and create long tunnels through the soil, which helps aerate and loosen it, creates channels for movement of water and oxygen, and allows plant roots to penetrate more easily. They help mix plant matter into the topsoil where beneficial microorganisms can decompose it. They consume organic matter such as fallen leaves, thereby recycling plant nutrients and increasing soil fertility. Worm castings (a.k.a. poop) are an excellent soil amendment since they’re rich in nutrients such as nitrogen, phosphorus, and potassium. Research even suggests that plants have improved disease resistance if planted in soil enriched with worm castings. Worms also provide a valuable source of food for birds, frogs, and other wildlife (not to mention being gobbled up by backyard chickens and fish on hooks).

Most of our native local species of worms have been destroyed or displaced by human activity; the kinds we usually see are descendants of hardier worms intentionally or accidentally introduced to North America by early European and Asian immigrants. There are now about 180 different species of earthworms in the U.S. and Canada, a third of which are non-native (including night crawlers). The typical garden earthworms are NOT the same as redworms or “red wigglers” (Eisenia foetida), the non-native species most commonly recommended for use in home worm composting.

Earthworms are primitive but fascinating creatures. They don’t have eyes, but they do have special light-detecting receptors. Light is a bad thing for creatures whose natural habitat is underground, and worms have evolved to move away from light sources, hence their burrowing instinct. They “hear” by detecting vibrations, and they produce mucus or “slime” in reaction to stress (e.g. being yanked from the ground). They also have voracious appetites: some species can eat their weight in organic matter every day.

Worms are hermaphroditic: each worm has both male and female reproductive organs in its elongated, muscular, tube-like body. Typically, two earthworms join side-by-side in opposing directions to mate, and each member of the pair produces an egg capsule from which one to several immature worms eventually emerge. Redworms are among the most prolific breeders.

In part due to its reproductive success, some Native American cultures revere the earthworm totem as a symbol of fertility, productive thought, and acceptance of emotions. In our modern society, the worm can represent either the beneficent (as in the sweet, bespectacled bookworm) or malicious (as in harmful software that lurks in the Internet).

A common earthworm with castings (Univ. of CA)













This is a good time to discredit a common misconception about worms. If a worm is cut in half by a shovel or by an over-enthusiastic tug from a curious child, the two parts won’t heal and live to create new worms. The head end (with its tiny brain and five hearts) can’t survive without the tail end (with its digestive system), and the worm simply dies.

You can use several techniques to encourage greater earthworm populations in your garden: (1) Avoid frequent tilling or cultivation of soil; (2) Minimize the use of synthetic fertilizers and pesticides, all of which disturb naturally occurring soil micro- and macro-organisms; (3) Allow leaf litter to remain on soil year-round, to provide a food source for worms; and (4) “Sheet mulch” bare soil, using layers of cardboard, mulch, and compost to keep soil cool and moist and to provide a source of organic material for worms to eat.

A word of caution: don’t dump unused live bait worms in a remote natural area. Many forest and mountain environments are naturally devoid of earthworms, and introducing them to those areas can be harmful. Forests often depend on a dense, protective, year-round layer of leaf litter, and earthworms will rapidly consume that thick organic mat.

For more about earthworms in our ecosystem, go online to and search for the article Earthworm Ecology in California, or read the book “The Earth Moved: On the Remarkable Achievements of Earthworms” by Amy Stewart.

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




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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

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