It’s Time to “Celebrate Spring!”

This is the time of year when gardens burst into full glory, with plenty of fresh spring growth, gorgeous blooms, and wonderful scents! (My enthusiastic note is tempered with a sympathetic nod to allergy sufferers, for whom this beautiful time of year can also be the most miserable.)

The show this season is even lovelier than in past years, thanks to our more normal winter rainfall and periodic spring showers. It’s a perfect time to get out and enjoy the colorful sights in your own garden and in your local surroundings.

If you’re looking for a fun and scenic little adventure without having to travel far, plan to attend an upcoming event presented by the San Joaquin County UC Master Gardeners: the 2016 Garden Tour. The theme of this year’s tour is “Celebrate Spring!”

The tour (a biennial event) will be held on Sunday, May 1 from 10:00 a.m. to 4:00 p.m. at various locations within the city of Stockton, and it promises to be an enjoyable, inspiring, and informative event.

This year’s garden tour features seven privately owned gardens and one public garden with three distinct areas, all in central Stockton for convenient access. Here’s a list of some of the many garden elements and features you can expect to enjoy during the tour:

  • A water-wise garden incorporating color, form, texture, and artificial turf
  • A lush and shady garden with an Asian flair
  • A scenic, woodland-type garden with a pond and expansive views
  • A terraced, bird-friendly back yard with garden art and an herb garden
  • A highly varied garden with entertainment spaces and whimsical features
  • A bountiful organic garden filled with vegetables and numerous fruit trees
  • One public garden that highlights different plant types: edibles, roses, and valley-appropriate California natives

In addition to the sheer enjoyment offered at each location, there will also be many educational resources available to tour-goers. Certified UC Master Gardeners will be available at each site to lead demonstrations, explain displays, and answer gardening-related questions. Free educational handouts relevant to each tour location will be provided. Important plants within each garden will be labeled with common name, scientific name, and cultural information for the benefit of visitors. Various University of California horticultural publications and San Joaquin Co. UC Master Gardener journals will be available for purchase either by cash or check.

Tickets to the 2016 Garden Tour are only $20.00 each if purchased in advance. The cost increases to $25.00 apiece if you buy tickets on May 1, the day of the event; all ticket purchases that day must be made at the University of the Pacific, Robb Family Garden, 1081 W. Mendocino Avenue.

Garden Tour tickets can be bought directly from the UC Master Gardener program in two ways:

  • At the UC Master Gardener Office, 2101 E. Earhart Avenue (off of Arch-Airport Road near the Stockton Airport). The office is open Monday through Friday from 8:00 a.m. to 5:00 p.m.
  • Online by credit card at the San Joaquin County UC Master Gardener website: April 24 is the last day to purchase tickets online and have them mailed to you. Tickets purchased online after April 24 will be held at a will call table at UOP’s Robb Family Garden (address above).

Tickets will also be available for purchase (cash or check) from UC Master Gardeners on April 23, 24, and 30 from 10:00 a.m. to 2:00 p.m. at two local nurseries:

  • Delta Tree Farms, 12900 N. Lower Sacramento Road, Lodi
  • Quail Lakes Nursery, 3404 Shadowbrook Drive, Stockton

Once you purchase tickets, you’ll receive a detailed brochure listing all the garden locations and their major features. The brochure also includes a map for general navigation. Light refreshments and water (for refilling personal water bottles) will be available at select garden sites.

Treat yourself to an inexpensive and fun day, and help support a valuable cause! Proceeds from the 2016 Garden Tour will help fund UC Master Gardener education and gardening outreach activities in San Joaquin County.

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


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Irrigation Tips for Water-Wise Gardens

Orchid Rockrose is a drought-tolerant, evergreen shrub with large, pink flowers in spring. It is widely available and easy to care for.

If scheduling irrigation were as simple as peeking out the kitchen window to see if things “look dry”, the Master Gardener program would barely be able to justify itself. Most of the problems we encounter stem directly or indirectly from water-related issues, especially with so many drought-tolerant plants and their mysterious water needs popping up all over town.

Drip irrigation has become very popular, but like any other cultural practice, must be done correctly to be effective. Because root systems are much larger than most people realize, a common mistake is to place one drip emitter next to a new plant and walk away forever, never adding new emitters to expand along with the ever-expaning roots. It’s important to encourage this expansion, which is key to the plant’s tolerance of drought.

Irrigation should be sufficiently deep (and wide) so that the entire root system is hydrated. Exactly how deep depends on the plant: ornamental grass and herbaceous perennial plant roots are in the top 8-12”, and the majority of shrub and tree roots are in the top 18-24”. A tool such as a screwdriver or trowel will allow you to check soil moisture several inches down. Scheduling will depend on many factors such as the time of year, your soil type, whether you have drip or pop-up spray, and the flow rate (measured in gallons per hour for drip and per minute for spray). Running drip for 10 minutes will barely wet the top 1/2” of soil, encouraging roots of ornamentals to grow right near the surface, making them more prone to drought. Help with drip irrigation can be found on the Sonoma County Master Gardener’s website:

Many water-wise plants do quite well on 2-3 deep waterings a month after a couple of growing seasons to get them established, but you will have to experiment to find the best schedule for your site conditions. Soil should be allowed to dry slightly between waterings for drought tolerant plants, though never to the point it becomes dusty. Bare soil can form a water-repellant “crust” on the surface, which increases run-off from irrigation (and rain); applying a 3-4” layer of organic mulch such as bark to the soil surface will both prevent this crust and retain more soil moisture.

What about California native plants? They evolved in our climate, so why should you water them at all? This seems logical enough; unfortunately, native plants are dependent on a compatible soil environment to hold and deliver this water to them. Decades of human activities have completely changed this environment, meaning no one has native soil, and everyone must provide at least some supplemental irrigation. Other factors contributing to the need for irrigation include groundwater depletion, less than average rainfall, and the fact that most homes are built high above grade so rain washes down gutters rather than recharging the local aquifer.

There are a small number of natives that do not require any supplemental irrigation, but they are accompanied by a strict requirement for excellent drainage. If working with your sandy soil is like a trip to the beach, go ahead and try xeric plants intolerant of heavy soil such as Flannel Bush (Fremontodendron californicum) or Woolly Blue Curls (Trichostema lanatum); Stocktonians are more likely to build bricks than sand castles with their soil, so it’s better to stick with less fussy plants that require irrigation now and again.

Improving drainage will increase rainwater percolation into your soil, which acts as a reservoir for the dry months, thereby reducing irrigation needs. The best way to achieve this is to improve soil microbial life by lightly mixing a 1” layer of compost into your soil and applying an organic mulch to the surface (do not mix it into the soil). You can also install a rain garden, which is basically a depression in the ground that gives rainwater a place to linger while it percolates into the soil. Plants selected for this area can take seasonal flooding but do not require as much water in the dry months. See this link for more details:

With all this talk about water-wise plants needing irrigation, you might be worried about not watering them enough, which brings me to my last point: you can definitely overwater water-wise plants, and unlike species adapted to wetter climates, they will not be as forgiving. Soil biology is easily altered by temperature and moisture, and certain pathogens thrive in hot, damp soil that water-wise plants never developed resistance to. You may see them initially growing faster with extra water, but don’t be fooled; this rapid growth is likely to be weak and susceptible to pests, and the stress of those soil pathogens will probably shorten the plant’s life considerably. Keep in mind that wilting leaves can be a sign of both over- and under-watering; the best way to know what’s happening is to check the soil. If it’s soggy, let the soil dry out a little before watering again.

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 You Need To Know About Landscape Fabric

Landscape fabric never stays in place

Many products claim they can end your weed woes. One such item is landscape fabric, a semi-permeable material made of woven polypropylene laid directly on the soil. For areas to be planted, slits are cut into the fabric where plants are to be placed.

Please don’t be fooled by the fix-it-all façade of this infamous product. Although landscape fabric offers some weed prevention, there are many long-term factors to consider:

The weeds will be back, even if you sprayed with herbicide, and they will be even more difficult to remove when their roots intertwine with the fabric. Landscape fabric can block some weeds, but others will germinate from underneath, or in soil that gradually collects on top.

Polypropylene is non-biodegradable. Unfortunately, this does not mean it will stay completely intact forever. Eventually it will break up into irritating shreds without any benefits to the soil.

Soil life is inhibited. Organic mulch placed on the surface will provide few soil benefits when there is fabric in the way. Fungal threads residing in soil that normally grow up into mulch for decomposition act as a “glue”, keeping mulch in place. Landscape fabric blocks this natural process, causing a “mobile mulch” effect, wherein bark is blown away in dry weather and floats away in storms. Air circulation is also reduced, which is another death-blow to soil organisms. If you have had landscape fabric down for years, you will often find sickly pale-colored, rock-hard soil underneath, signs of soil lacking in abundant life.

Slower rain percolation happens when the soil becomes dead, hardening into an impermeable medium turning rainwater into run-off. With rain being so scarce, it’s important to capture this precious resource on-site to help recharge the aquifer.

Applying fertilizer and compost is difficult because you have to pull back the fabric to apply anything and then put it back down again. Who wants to do this every year? Of course, the lack of oxygen destroys the soil life necessary for utilizing these amendments and making nutrients available to your plants, rendering compost and fertilizer moot.

Roots are unhappy because they cannot grow well in soil lacking microbial life and oxygen. The only air and life is near the surface, which is where you find shrub and tree roots after a few years under landscape fabric. Roots close to the surface are much more prone to drought stress than deep-rooted ones. This can be combatted by placing drip irrigation under the fabric, but keep in mind the difficult in inspecting and maintaining a system that is essentially buried.

It’s ugly. Eventually your garden will look like a discount bin of of frumpy, black shirts half-buried in dirt. Mulch is often used to cover landscape fabric, but what’s the point of having both? Frumpy fabric won’t provide any weed prevention (unless you have weeds with fashion sense). Using 3″-4″ of organic mulch alone is better in the long term.

Landscape fabric is required under gravel pathways and in drainage installations, where permeability is desired, but soil health is not important. There will still be some weeds, but this is unavoidable in any case, no matter what advertisers say! Even if you are not convinced to avoid placing landscape fabric under your plants, avoid using plastic sheets under ornamentals, as the problems listed above will be multiplied tenfold, particularly when it comes to aesthetics and soil health.

Alternatives to weed control often involve changing cultural practices, though it always depends on what the problem is. Whether you are battling a few Dandelions or a platoon of Yellow Star Thistle, begin by properly identifying the plant(s). See the UC Integrated Pest Management website for advice on how to deal with different species:

Weed management queries and other gardening related questions can be directed to the UC Master Gardeners at 209-953-6112. More information can be found on our website:


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Make garden space by growing upward

A metal pyramid hosts a Mandevilla 'Alice Dupont'

Back yards in today’s subdivisions tend to be on the small side, though I have lived in a couple of homes built in 1912 that had small back yards as well. Of course gardens don’t need to be limited to back yards as the trend is to make every part of the property bloom with plants other than lawn. However, as gardeners we have to make do with whatever our garden spaces are. One way to cope with limited garden space is to grow upward using trellises or other techniques.

If you are growing grapes, black berries, kiwis, luffas, chayote, pole beans, peas, cucumbers, tomatoes, cantaloupe or Dahlias, it is either necessary and/or possible to grow them vertically on trellising, stakes or cages.  Of course growing cantaloupes on a trellis is a little tricky in that melons need to be supported by slings attached to the trellis.

Trellises can be made from lots of material.  Wood, bamboo, PVC pipe, scrap metal, iron or copper pipe, old netting, or woven wire fencing can all be pressed into service.  If using wood, cedar, cypress, redwood or other rot resistant varieties are best. The kind of material and stoutness depends on the plants involved. For example, if you are trellising kiwis, you will need a substantial trellis, perhaps of steel pipe, as the crop from a single kiwi plant can weigh over 200 lbs.  Similarly, Wisteria vines can be stout and vigorous requiring a strong structure.

Trellises for beans, peas or sweet peas can be wire, string or netting. I use old sheep fencing that I attach to stakes for my peas. For beans I use an old modified swing set which is strung with sisal twine that works quite well. However, a simple teepee built of wood can also be used for beans and peas. A chayote trellis also needs to be stout for a heavy crop and I repurposed some old steel 2 inch well pipe for mine.

Tomatoes are best when caged or grown on a trellis to keep fruit from the molds and other destroyers lurking on the soil. There are several approaches that work for tomatoes and the one I prefer is to make cages from concrete reinforcing wire or heavy woven wire. Cages that are about 6 ft. tall and 18-20 inches in diameter are good for indeterminate varieties like Ace and Early Girl which can top 6 ft.  If you are growing determinate types like Shady Lady, Roma or Celebrity, a 3.5 ft. high cage will work. If you are lucky, you might find a commercial tomato cage that works, but I have had little luck.

Many flowers also grow upward. Large, fragrant evening-blooming moon flowers can be trained on string to fences, posts or a trellis. Climbing roses, sweet peas, Passion vine, Mandevilla, Clematis, Wisteria, Honeysuckle, morning glories and trumpet vine all require something to climb on. My Chinese Wisteria is on a trellis fashioned out of old pipe that was lying around the homestead. I also have a Japanese Wisteria trained as a tree, supported by a steel stake. There is also the option of letting vines such as Clematis and morning glory climb on shrubs or trees.

A Japanese Wisteria (floribunda) trained as a tree with a steel stake for support.

I have two trumpet vines (Campsis radicans) which are very attractive to hummingbirds. One is fixed to a 14 ft. post in my yard and the other is growing on an old walnut tree and has been there for over 50 years. It blooms in the top of the walnut and drops spent, attractive flowers on my patio each summer.

We can also espalier fruit trees along a south facing fence or wall, creating a more two dimensional effect to conserve space for other plants. Pears and Apples lend themselves well to espalier but stone fruits such as plums, apricots and peaches on dwarf rootstocks can also be trained with proper attention to pruning.  It may take more time to train these plants, but it is a challenge that is rewarding with tasty fruit from a small space.

To provide a place to climb can be also be an opportunity to use or fashion some art in the garden. I have built 3 pyramidal trellises from scrap steel. They have a rustic, artsy look to them. One of them hosted a Mandevilla ‘Alice DuPont’ this past summer and the other one a Clematis.  Since not everyone can weld, it is also possible to make attractive pyramid trellises using wood. Whatever your whimsy or your medium for trellising, have fun growing up.

A note for gardeners: Delta College has plants for sale on Fridays from 10 AM to 3 PM at their greenhouse. On April 16th from 9AM to 3PM, Linden Community Garden Club has its annual plant sale at the Methodist Church in Linden, features herbs, tomatoes, peppers, perennials and many other plants.

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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Garden legacies and restoration of fine art gardens

Gardens are an important part of modern life as they have been throughout history. A peaceful beauty spot removed from some of the hustle and bustle of modern cities. Once upon a time the planet was a natural garden of complex ecosystems co-evolving with animal life. While there are still ecosystems left, most are modified or degraded by human hands. Most humans living in cities have little access to natural landscapes, so we create our own peaceful refuges and/or visit public gardens. There are gardens that are art and there are gardens that are just for the joy of gardening. I garden for the joy, but I am conscious of the contributions to my landscape of the previous owners and build upon their legacy to me. The old Camellias, peonies, roses, loquats, olives, redbuds, horse chestnut and oak trees are the bones of my landscape to which I have added many plants. Today we create our own little backyard ecosystems—native plants, pollinator gardens or wildlife friendly gardens. I have always considered gardens to be constantly evolving as we try new ideas, new plants, some of which thrive and some we learn to give up on. However, this is less true of historic fine art gardens which are maintained or restored to the original design. Fine art is well protected in our society. I wonder if Leonardo de Vince ever thought that his Mona Lisa would be so valuable someday and protectively hung in the Louvre in Paris. Gardens can also be creative art forms, but they are living art forms requiring a lot of maintenance. They cannot be hung in a museum. All that creative arrangement of plants will perish in a year or so, if gardeners are absent. Thus many have perished and have had to be gone for years before someone endeavored to recreate and maintain them. One example is the restoration of Monet’s famous gardens at Giverny, France. Monet was as great with colors in the garden and using a spade as he was with a palette and brush in the studio. Monet produced hundreds of paintings of the 6-acre gardens at Giverny, after landscaping the tract himself. He is quoted as saying “More than anything, I must have flowers, always, always.” Giverny’s gardens were maintained by the family after Monet’s death in 1926, but following WWII, it was not well maintained. The property was being restored as a public garden in 1985 when Elizabeth Murray, a Californian, became determined to join the project. At 32, she quit her job and moved to France and spent six months at Giverny to help restore the gardens. She has since made many museum-collected photographs of the gardens. Her selfless act turned out to be a career path. Historic garden restoration is now a defined profession. Many universities in Great Britain offer Master degrees in the subject. Here in California, The California Garden and Historical Landscape Society (CGLHS) came into being in 1995. Its mission is to: Celebrate the beauty and diversity of California’s historic gardens and landscapes by education. One of the many problems in restoration of gardens is finding the replacements for the original plant materials. Many of the plants used in gardens of yesteryear are no longer in commercial trade, and sometimes the gardener did not write down the specific plant names of the original plants. This website contains a long list of resources to help in finding the right plant for its historic place in the restored landscape. Friends of Hearst Castle have undertaken a restoration of the gardens there to return them to the earlier vision of William R. Hearst and his architect, Julia Morgan. Castle staff identified the original plant species and their placement on the grounds of the world-famous estate located in San Simeon. The research utilized old photographs, historical records and letters written by Hearst and Morgan. Funding of the project was from a variety of sources including the California Garden Clubs, Inc. an umbrella organization for the hundreds of garden clubs in California which pitched in. Most of us are not rich and famous or live in places of historic importance though we may have extensive gardens. It is sad to contemplate gardens being destroyed or neglected, but such is life and the lack of control over future circumstances. In my own case, perhaps a more enlightened gardener will actually endeavor to create a landscape more in keeping with California’s native habitats and be a boon to pollinators and wildlife. I hope so. One of my favorite public gardens is the Mendocino Coast Botanical Garden at Fort Bragg, but I have many more to see. If you desire to add to your bucket list some outstanding public gardens in California, restored or just beautiful, you can find a list here: 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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Overcoming the Fear of Water-Wise Landscaping

Change is hard. Grass is a familiar and fairly standard planting in California landscapes, and accepting something other than a front yard lawn can be difficult for many people, for many reasons.

Many homeowners’ associations (HOAs) have outdated and restrictive bylaws that mandate a certain percentage of lawn in front yards. Until recently, homeowners bound by such regulations couldn’t undertake a full-scale landscape conversion; they were also subject to fines for allowing lawns to go brown. Fortunately, under California Assembly Bill 2104 (effective January 1, 2015), HOAs can no longer penalize residents for replacing lawns or for conserving water.

With luck, this article will help dispel some of the misconceptions and concerns about lawn removal and water-wise landscaping, particularly if you’re an undecided homeowner, an HOA board member, or an anxious neighbor.

#1: Removing lawns will ruin the character of the neighborhood.

Contrary to common belief, a low-water-use landscape doesn’t mean “ugly” or a desert-like scene with cacti scattered in a patch of rock and gravel. There is a huge palette of durable, attractive, and colorful plants that thrive in our climate, from places around the world that share our hot, dry summers and coastal influence (Mediterranean areas, South Africa, western and southern Australia, central Chile, and more).

Undoing the uniformity of a continuous chain of green lawns can be a positive change! Landscapes don’t need to look like a golf course or country club to be appealing or to be a community asset. Embrace variety, and imagine plants with multihued foliage, stunning blooms, and environmental benefits, all of which a water-wise garden can provide.

Colorful, early spring foliage and blooms in the Learning Landscape demonstration garden at the Robert J. Cabral Agricultural Center in Stockton. (Photo courtesy of Karrie Reid)


Penstemon and yarrow in the Learning Landscape. (Photo courtesy of Karrie Reid)























#2: A new landscape will be too expensive.

The initial cost for lawn removal, landscape design, and installation of new plants and irrigation systems can be high. On the other hand, the eventual benefits — including substantially reduced water bills, elimination of weekly lawn mowing services, and no need to purchase lawn care products — can result in significant long-term savings. Programs such as the State of California’s Save Our Water turf replacement rebate can also make a landscape conversion more affordable.

#3: Yards without lawns aren’t green enough.

Water-wise gardens do have a different aesthetic than lawns, but that isn’t bad. Those flat green carpets can be traded for other green plants with colorful flowers, varied heights, and interesting foliage. Or to retain a lawn-like look, opt for unthirsty low-growing groundcovers such as Kurapia, Silver Carpet (Dymondia margaretae), or Myoporum (Myoporum parvifolium).

Also, keep in mind that most residential lawns aren’t “green” in the environmental sense. They’re typically overwatered, over-fertilized, and regularly treated with pesticides; this results in polluted runoff, excessive growth, and high water and maintenance demands.

#4: Low-water-use plants look bad most of the year.

Remember that dormancy is a natural part of the life cycle of all perennial plants, not just California natives and other water-thrifty plants. Most plants take a break during cold weather, halting their growth and bloom until warmer weather arrives. All deciduous trees and shrubs lose their leaves some time during the year, exposing bare branches. Even typical lawns have dormant periods: water-thrifty warm-season grasses naturally turn brown in the winter months; cool-season grasses slow their growth in hot weather (and require lots of water to stay lush and green). Prudent plant selection, placement, and care are the keys to a water-wise garden with year-round appeal.

#5: New landscapes take “too long” to look good.

Our fast-paced culture often demands instant results, but good things are worth the wait. Plants that look meager and widely spaced when first installed will soon thrive and reach their mature size without being overcrowded. Lawn removal and soil treatment techniques such as sheet mulching and soil solarization — which are temporarily unsightly and can take several months to produce the desired results — reduce weeds and improve both the nutrient content and long-term health of the soil. Patience has its rewards.

Explore the possibilities by visiting the Learning Landscape (demonstration garden at Stockton’s Robert J. Cabral Agricultural Center) or by participating in upcoming local garden tours: the 2016 Garden Tour by the U.C. San Joaquin Master Gardeners; the 2016 Elk Grove Greener Gardens Tour; or the 2016 Gardens Gone Native Tour by the California Native Plant Society.

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

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A Guide to Wise Tree Selection

Spring is almost here, accompanied by the nearly irresistible urge to plant! Browsing nurseries for plants is an exciting annual rite of passage for every garden lover, and who can resist an impulse buy here or there? But spur-of-the-moment tree selection is one mistake that should be avoided at all costs.

The best advice to heed before selecting and planting a tree is research, research, RESEARCH. After considering all the benefits a tree might offer (beautiful fall color; attractive form; seasonal bloom; cooling shade; decorative or edible fruit) it’s important to carefully weigh those attributes against a tree’s potential pitfalls (leaf or fruit litter; invasive roots; extensive surface roots; brittle branches; susceptibility to pests or diseases; too large size when mature; pruning requirements). The caveat of “right plant, right place” is especially important when choosing and locating a tree.

One of the most crucial considerations is a tree’s mature size. That adorable little specimen you discover in a nursery container won’t stay that way forever. Most residential properties are too small to accommodate the ultimate height and width of many tree species. Improperly planting a large-growing tree in a tiny lot or narrow side yard can lead to a host of problems: structural damage to a house; interference with overhead utility lines; severe and damaging pruning to keep the tree within a tight space; and roots that heave pavement, crack foundations, or damage plumbing.

A tree’s growth rate is another important consideration. Homeowners and inexperienced landscapers often select fast-growing species of trees (e.g. Chinese tallow trees, fruitless mulberries, tulip trees), knowing the small saplings will soon provide plentiful shade. Unfortunately, many fast-growing trees are also structurally weak and prone to breakage. They also have vigorous and often damaging roots that typically outcompete other nearby plants for water and nutrients.

Different trees vary in their requirements for water use, soil type/pH, and climate zone, all of which should factor into your decision. Before shopping for and planting trees, measure your available space carefully, know the location of underground utilities (including septic systems), and invest in a soil test. Given our ongoing water supply concerns, consider limiting your search to low-water-use trees suitable for our Sunset Climate Zone 14.

A disheartening sight: palettes full of coast redwoods (Sequoia sempervirens) at a local warehouse store. (Photo by Kathy Ikeda)

One tree commonly but improperly planted in the Central Valley is the coast redwood (Sequoia sempervirens). Think about its name to understand why it’s a poor choice: it’s native to coastal areas of northern California that have ample water and cool, foggy summer days (not at all like the dry, hot summers in our area). A mature redwood requires hundreds of gallons of water a day in order to thrive. It’s far better to enjoy redwoods in their native habitat than to plant them locally, where they either contribute to depleting our limited water supply or suffer and die from persistent heat and drought stress. 

One suitable alternative to the coast redwood is the incense cedar (Calocedrus decurrens). It’s also an evergreen conifer with a symmetrical, pyramidal form, but it has a smaller stature when full-grown (75-90 feet high and 8-15 feet wide, as compared to 100-plus feet high and 25-35 feet wide for redwoods). Best of all, the incense cedar is very tolerant of heat, drought, and poor soils once established, and its cascading foliage has a pleasantly spicy fragrance.

If all these considerations seem bewildering, rest assured that the time and effort you invest in proper tree selection will potentially prevent many headaches and expenses in the future. There are lots of excellent sources of information on various tree species and their attributes. The Sunset Western Garden Book is a go-to standard, with tree information tailored to the western states. The San Joaquin County Environmental Horticulture website has a “Right Tree, Right Place” page with basic tree selection guidance and references. Knowledgeable nursery staff can also provide expert advice.

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

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Small Trees for Urban Gardens

Feathery Plumes on Mountain Mahogany seeds

With spring planting in full swing, now is a good time to select a new tree. For those of us with small gardens, however, the towering majesty of Valley Oaks or Plane Trees can create serious issues when invasive root systems and branches wreak havoc with driveways and utility lines.

To solve this dilemma, try a low-water use shrubby tree, which is a plant that naturally matures into a large shrub, but can be trained into a small tree. In terms of design, they provide a height element while remaining in proportion to a small garden. As with larger trees, small trees can also offer habitat for birds and other wildlife.

Shrubby trees grow to 15′ – 20’ tall and wide, though some can become larger over time. Not all shrubs are suitable to be trained into a small tree; within this category, there is also variation in the possible length of bare trunk between the ground and the lowest side branch. This is important when determining what to plant underneath, how much pedestrian clearance you will have, and how it will be pruned. Also keep in mind that their small stature means that the widest part of the canopy is closer to the ground, making some shrubby trees a poor choice for narrow areas.

If you need clearance around the tree it will need a longer trunk, meaning the lowest side branches are high enough so activities under the tree don’t result in bruised foreheads. The following species are well-suited to this purpose (but can also be grown with short trunks, if desired):

Crape Myrtle (Lagerstroemia indica) is very popular with it’s showy, pink flowers blooming all summer long. They are commonly found along sidewalks where they are trained into trees that can be walked under. Thrifty with water, tolerant of our heat, and possessing beautiful bark for display in winter dormancy, these make excellent small trees for the home garden. 

Fruitless Olive Trees (Olea europaea) have the gnarled wood, silvery foliage, and resilience of regular olive trees, but without the mess. Although they can become large with age, they are very slow-growing when watered properly (i.e. not excessively), and it is feasible to keep them within bounds. One word of caution: Fruitless Olive Trees come in large planter “boxes” at the nursery and may require special equipment to install. The smallest size is typically a 24″ box.

‘Marina’ Madrone (Arbutus ‘Marina’) is a UC Davis Arboretum All-Star ( with delicate pink flowers in late winter and bright, evergreen foliage that contrasts nicely with the wine-red bark. Great for hummingbirds.

Some shrubby trees are better trained into specimens with short bare trunks in which the lowest side branch is 6”-12” above the ground (this is not exact and varies according to what you want and the conditions the tree will be growing in):

Lemon Bottlebrush (Callistemon citrinus) is drought-tolerant and evergreen with brilliant red blooms appealing to hummingbirds and honey bees alike. The branches display an arching habit and lemony-scented foliage when crushed.  

Mountain Mahogany (Cercocarpus betuloides) is an evergreen California native with dark brown bark and lustrous, scallop-shaped foliage. The most interesting feature is the feathery plume attached to each seed, covering the tree all summer in a beautiful display when backlit by the sun (see picture above). The seeds also provide good forage for birds and small mammals.

Pineapple Guava (Acca sellowiana) has fuzzy, oval-shaped foliage, which is dark green above, and silvery underneath. The pink and red flowers with showy stamens bursting forth like fireworks appear for two weeks; this short bloom season is countered by the attractive, dense foliage, which remains all year. It is fairly drought-tolerant, but will need some extra water and a second Pineapple Guava to fruit well.

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 at





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Managing Bermuda: Dreams vs Reality

sheet mulching in progress

The weather is crisp, the leaves are falling, the first rains of autumn will soon arrive, all of which means the best time to plant is now. The only task left is to rip out that Bermuda lawn today, and I’ll be set for planting by tomorrow…

If this has been your dream of late, be glad it isn’t actually fall; you can still avoid one of the most common pitfalls of Bermuda grass control: last-minute management. Dreams of an herbicide-free operation can also crash into a harsh reality: only in some situations will this work. Your site conditions determine the best management strategy in spite of your best ecological intentions.

Have you noticed a lack of the word “eliminate” and “kill”? It’s because this isn’t possible with Bermuda. The main reason is that it spreads by above-ground runners called stolons, which are very difficult to kill. Spading or hand-pulling is ineffective, as there will always be little bits left in the soil; in fact, only a 1/4” piece of the stolon is required to grow a whole new plant.

Removing Bermuda with a sod cutter or rototilling chops the stolons up into so many pieces, you may as well do nothing. Mechanical removal is often combined with two other practices, neither of which is effective. The first is to deprive the lawn of summer irrigation, thinking this will kill it. Truth: Bermuda goes dormant and will reawaken the next spring after receiving water from winter rains and the water you must give your new plants to establish them. The second is applying landscape fabric to smother new Bermuda sprouts. Truth: landscape fabric is a short-term solution, wreaking long-term havoc.

Spraying with a systemic herbicide such as glyphosate improves the efficacy of both methods, but the lawn must be healthy so it can draw the chemical down into the roots, which are killed. Rototilling can work without herbicides if done so the stolons are left on the surface to dry, an action requiring several weeks of hot, dry weather. A pre-emergent may also be necessary to prevent seeds from germinating, which are brought to the surface by the soil disturbance.

You can “cook” Bermuda to death by practicing soil solarization, which covers an area with clear plastic sheets for 6 weeks. This only works if the grass receives a full 8 hours of sun in the height of summer (July-August), and is monitored closely for holes, which allow heat to escape unless taped up. There are several factors critical to the success of this method; more information can be found at:

Sheet mulching is a method in which cardboard is placed directly on top of the lawn, followed by several inches of mulch. This is the best method for garden health, as the materials break down and provide food for soil microbes, which in turn create a nurturing environment for your plants. Unfortunately, Bermuda comes right up through the cardboard (sheet mulching works fine on Fescue lawns without herbicide). If you have Bermuda, you will need to spray a systemic herbicide before mulching (remember: the lawn must be healthy and actively growing). Manufacturers have made cardboard as tough and water-repellant as a paper-based product can be, so don’t pile on excess layers, as water and air will have a hard time getting to the soil, limiting the microbial activity essential to decomposition.

Shading out Bermuda by allowing trees or shrubs to block sunlight can work, and doesn’t require any herbicides. This process may already have started in parts of your landscape, or you may have just now gotten the idea and are heading to the nursery for trees and shrubs. Be forewarned: the death of an otherwise healthy lawn by gradual starvation (lack of sun) is an ugly, sad process taking many years. Picky neighbors might make this method best for the backyard.

These removal techniques require careful planning; skipping steps to save time or because you had a family vacation in the middle of the process can mean the difference between success and a yard full of Bermuda next summer. Be realistic about the predictability of your schedule. Can you stick around to check plastic sheets for holes? Can you start rototilling early enough so it doesn’t rain while the stolons are drying? Can you complete the sheet mulching process at least 6 months before fall planting?

I have only given a bare outline of Bermuda grass management. Visit the UC Integrated Pest Management website for more details:

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 are wonderful fruit for our valley

Here are some citrus stories—the good, bad and the ugly. First, what is so good about citrus? Citrus is easy to grow and pretty pest free as plants go and we live in a wonderful climate where it can thrive. Citrus is a healthy food; oranges, lemons, grapefruit, pummelos, kumquats and limes are all good sources of vitamins C, but oranges have the highest Vitamin C content. Oranges also contain fiber, potassium and choline, which are all good for your heart. Eating oranges is healthier than drinking the juice if you are worried about calories. The fiber, the white pith in oranges, helps you to feel full and reduces sugar uptake.

My love and fascination with citrus has a history. Growing up in New Jersey in the 1940’s, citrus had to travel a long way and was always traditionally included in Christmas stockings as a special treat. When my brother and his wife visited me from New Jersey in 1983, they were awed to have fresh squeezed orange juice for breakfast from my own Valencia tree that had likely been planted in the 1940’s or earlier. It lasted until 3 years ago when it was removed due to old age and decline.

I planted a Meyer lemon when I moved here in 1976 and it is still producing lots of lemons each year. There was an old Eureka lemon here, but it succumbed soon after I arrived. There were also 2 navel oranges, a ‘Washington’ and a ‘Robertson’ and they are still thriving and productive 40 years later.

There was also a pummelo here with a story behind it as told to me by the previous owner, a member of the Grupe family. The children of a related family that owned the Stockton Hotel would come out to play with the kids on the farm and they brought some pummelo seeds given to them by a Chinese chef at the hotel. They planted the seeds and a large pummelo tree is still producing. This likely occurred in the 1930’s. The point to these stories is that once established and cared for, citrus can be enjoyed for a lifetime or more.

Blood oranges are delicious and make a colorful addition to fruit salads.

Subsequently, I have planted a ‘Lisbon’ lemon which is more cold tolerant than ‘Eureka’. It has produced a hugh crop in its fifth year. I have also planted a Blood Orange with intensely dark red, sweet flesh and a tangerine. I also replanted a Valencia, which is a great juice orange. The one tree I don’t have is a lime, as it is too cold here for good survival. Occasional visits of Arctic fronts can raise havoc with citrus. For a listing of citrus available check out this grower site:

Citrus are relatively pest free, but there are a few to watch out for. Brown scale insects will reduce tree vigor see:  Keep ants out of your citrus trees because they will protect brown scale insects from parasites and predators in order to feed on scale honeydew. A band of Tanglefoot pest barrier on the tree trunk will usually keep the ants away.

Unfortunately, new pests have arrived. The citrus leaf miner, Phyllocnistis citrella, arrived in 2000. The larva of this pest makes tunnels through young citrus leaves. They are only damaging to new leaves and are not a major pest to deal with here because summer heat tends to suppress their numbers.

Now, I bring you the really ugly citrus story. An Asian citrus psyllid, Diaphorina citri, has recently arrived which has the potential to wreak havoc on citrus. The adult psyllid is small brown insect about the size of an aphid and it causes leaf distortion and stem die back. However, the real problem is that it is a vector for huanglongbing disease (HLB) also called citrus greening disease.

HLB is a bacterial disease and it is not yet established in California. However, it has spread throughout the Florida citrus regions causing devastation to the industry there. There is no cure. One tree was found infected in Southern California and was removed, but the danger is that it could come again and the vector is now here. It has the potential to ruin our citrus industry and our back yard citrus too. About 60 percent of California homeowners have backyard citrus. For more information, go to this site:  For more information on the psyllid finds and psyllid quarantine areas in San Joaquin County, go to this site:  Let’s hope we can continue to enjoy the benefits of citrus in California, by keeping this disease out.

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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  • Blog Authors

    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

    Nadia Zane

    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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