Controlling snails and slugs

How many times have you wandered into your garden on a cool weekend morning, only to discover telltale slime trails, holes chewed in the leaves of just-planted ornamentals, or vegetable seedlings chewed to the ground? Or worse yet, walked unsuspectingly down a pathway only to smash a slimy slug or crunch a juicy snail beneath your feet?

Common garden snails and slugs are such ubiquitous pests that the battle to control them never ends. This year, soaking rains and lush new plant growth have provided a plentiful selection of tender morsels for them to eat.

Brown garden snail and damage on citrus fruit. (Photo courtesy of the University of California)

Gray garden slugs (Photo by Jack Kelly Clark, UC IPM)

The most common snails and slugs in our California gardens are non-native; in fact, the brown garden snail was originally introduced to the U.S. as food. But, since most folks would rather not snack on them, let’s look at other ways to reduce their population!

Cultural control methods involve eliminating the environmental conditions that snails and slugs prefer. When possible, replace plants susceptible to chewing damage with others that resist the pests, such as California poppy, lantana, lavender, ornamental grasses, rosemary, sages, and stiff-leaved or woody plants. Switch from sprinklers to drip irrigation to minimize excess surface moisture. Watch for dark, damp hiding places and modify them to be less attractive.

One very effective method of reducing snail and slug populations is to hand pick them regularly. It’s best to do this after dark, early in the morning, or after a period of rain or irrigation, since snails and slugs are nocturnal and most active in moist conditions. Picking up snails by their hard shells is relatively easy. Slugs are another matter; when disturbed, they contract their muscles and exude slime to become slippery, almost-impossible-to-grip lumps. Try scooping them up with an old spoon or a latex-gloved hand.

If you find hand-picking too distasteful, try enlisting your children or grandchildren in a nighttime “treasure hunt.” Kids armed with flashlights and a ready-made disposal system (a small pail or zip-closure plastic bag partially filled with soapy water) can turn the search into a fun contest.

Barriers are a method of non-lethal snail and slug control. Copper barriers are most effective at keeping the pests away from treasured plants; the metal reacts with slime secretions to create a shock-like sensation. Buy copper flashing, foil, or mesh, trim it into strips, then wrap it around tree trunks and containers or place it along the edges of planter beds. Copper sulfate (alone or mixed with hydrated lime) can also be brushed on surfaces as a repellant.

Abrasives substances that irritate the muscular “foot” of snails and slugs can also be used as barriers. Simply place dry ashes or food grade diatomaceous earth (DE) on the soil around planting areas, in bands about 3 inches wide. This technique is best used in small garden areas (since the abrasives must be used in relatively large quantities) and in areas that don’t get wet (since they lose their effectiveness when damp). Be sure the area you encircle is free of snails and slugs or you will keep them near the plants you’re trying to protect.

Traps can also be an easy and effective method of control. One approach is to place wooden boards or overturned pots on the ground. Snails and slugs will hide underneath them during the night, and in the morning they can be scraped off and disposed of.

Beer traps are another non-toxic method of attracting and killing snails and slugs, but they have a few disadvantages. They must be cleaned and refilled frequently; they only work within a radius of a few feet, since it’s the odor of fermented sugar that attracts the fleshy pests; and lots of traps are needed to reduce snail/slug populations. Rather than using a perfectly good beverage, make a concoction that will ferment and entice just as effectively as beer. Measure one tablespoon each of yeast, flour, and sugar, mix with one cup of water, and pour into high-walled containers with narrow openings.

Low-toxicity baits are another option for snail and slug control. Pellets or granules containing iron phosphate (Sluggo, Escar-Go) are the safest for children, pets, and wildlife. Sprinkle them around affected plants—do not mound bait in piles—and always follow application instructions.

Avoid poisonous means of snail and slug control whenever possible. Many products contain metaldehyde, which is attractive and very toxic to dogs, cats, birds, and other wildlife. Never place these baits where children or pets can reach them, and do not apply them on or near plants, especially those being grown for food. Don’t use metaldehyde-based products that also contain carbaryl, since it’s toxic to earthworms and other beneficial soil-dwelling organisms.

For more specific information and guidance, see U.C. Integrated Pest Management (IPM) Publication 7427, “Snails and Slugs” (

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


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Creating a Hummingbird Habitat

Do you love to watch hummingbirds fly around your garden? Many gardeners are fascinated with the beauty and aerobatics of hummingbirds. The key to attracting hummingbirds to your yard is to plant lots of flowers and provide the habitat that will give them shade, shelter, food, and security. These birds are loyal and once they find a habitat that satisfies their needs, they faithfully return year after year. Feeding hummingbirds for your personal enjoyment also helps the eco-system. These birds are pollinators and play an important role in the life cycle of flowering plants.

Did you know: There are 340 species of hummingbirds (16 of which actually breed in the United States) making them the second most diverse bird family on earth. Hummingbirds are the tiniest of all birds, weighing less than an ounce and measuring only 3 inches long. Their brightly-colored, iridescent feathers and quick movements make them appear as living sun catchers—hence their nickname, flying jewels. They have a unique ability to fly in any direction, even backward, with their wings beating up to 80 beats per second.

Here are a few things to keep in mind when creating a hummingbird habitat.

Location: Before you start planting a hummingbird garden, the first thing that needs to be picked out is the location. The hummingbird garden needs to be positioned where you can see it; otherwise, what is the fun of attracting the hummingbirds in the first place.

Flowers: Brightly–colored flowers that are tubular hold the most nectar, and are particularly attractive to hummingbirds. Hummingbirds are very visual creatures and have excellent vision and do not rely on smell. The best hummingbird gardens will include flowers that bloom at different times so hummingbirds always have an available food source, no matter when they visit. Make sure to deadhead spent flowers to enhance blooming.

Water: Hummingbirds need water to drink and to bathe. They prefer moving water sources such as sprinklers, fountains, waterfalls, misters and drippers and will often perch in a spray or fly through moving water to cool off or bathe. A small birdbath or even a shallow bowl with rocks works very well for hummingbirds to perch and drink water. All types of water sources should be kept fresh and clean. Position the water near nectar-rich flowers to make it even more attractive to hummingbirds.

Feeders: Nectar feeders are one of the most common ways to attract hummingbirds to your yard. A wide range of feeder styles is available and may come with wasp, hornet and ant guards. They are often colored red to help attract hummingbirds.

Hummingbird feeders impose a responsibility on the provider. To be safe, they must be clean, and that is a challenge in hot weather. The solution should be changed at least every other day, even if no hummingbirds are using it, so that it doesn’t ferment or get moldy. Every filling, you should flush the feeder with hot tap water and clean with a tooth brush or bottle brush. Most experts advise against using soap or detergent.  If all this is too much trouble, just plant the flowers and skip the artificial feeders. You’ll still attract hummingbirds, and you won’t be harming them with unsanitary feeders.

Nectar is easy to make for your feeders.  Boil four cups of water and stir in one cup of white sugar, let it cool and pour into clean feeders. It is recommended to avoid honey, which can cause a fatal fungal infection on the birds’ tongues. You do not need to add food coloring to the solution, the red color on the feeder is sufficient. If your feeder does not have any red on it, attach red flagging tape to the feeder or hanger. You can store the excess syrup in the refrigerator for a week or two. If the ants find your feeder you can apply petroleum jelly to the wire hanger to prevent them from getting to the nectar.

Hummingbirds are territorial and are not likely to share “their” feeders. So, hang more feeders far enough apart to attract more birds.

Insects: While hummingbirds are most well known for their fondness for nectar, they also eat a large quantity of insects, including gnats, aphids, and spiders. This protein is especially critical during the nesting season, when young hummingbirds need plenty of protein for proper growth. To attract hummingbirds to backyard insects, avoid using pesticides or insecticides that will kill off this food source.

Perches: Hummingbirds do not walk or hop but do perch about 80% of their life. Providing perches such as slender poles, clotheslines, thin vines, trellises, wires and multiple levels of shrubbery will give birds suitable shelter. At the same time, because many hummingbirds are very aggressive, they will prefer perches that also have good fields of view to protect their territories. A perch also supplies a spot “preening”, which is removing built up debris in their feathers.

Nesting Spots: Hummingbirds build their nests mostly in trees and shrubs. Providing sheltered, safe areas of plants for the birds to nest will make a backyard more attractive. You can supply suitable nesting materials including fine natural cotton and animal fur to attract nesting birds. Spider silk is especially attractive for nesting hummingbirds, because the elasticity of the silk is essential for their nests and female hummers use the silk to bind their nests together.

I hope you will think about trying to welcome these marvelous gifts of nature to your garden. With a few easy additions you can turn your yard into a hummingbird haven.

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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Ants and Aphids: A Pesky Partnership

Convergent lady beetle feasting on an aphid

Late spring is prime time for one of our “favorite” plant pests: aphids. Temperatures are averaging in the 70s, and plants are still flush with tender, new growth from an unusually wet winter. Turn over a leaf, and you might see itsy-bitsy insects in a variety of colors, from lime green to brown, red or black, depending on the species. They are generally less than a quarter-inch in length, and difficult to see in detail without a microscope.

How could something so small damage your plants? Their power lies in numbers; females can give birth to 12 live young per day during the growing season. These newborn nymphs can become reproducing adults in as little as 7 days, meaning colonies can grow quickly when conditions are right. All these little mouths require feeding, which is achieved by a long, slender mouthpart that pierces plant tissue and sucks out the sap.

While aphid populations are low, their presence often goes unnoticed, but larger parties can cause more serious damage. Typical damage looks like yellowing, distorted foliage at the tender growth of shoots where the aphid’s favorite food resides. Aphids secrete the excess sugars as a liquid called “honeydew,” which grows a fungus called black sooty mold, creating a harmless but unsightly mess. Their feeding can also transmit viruses. Vegetables such squash, lettuce, beets, and potatoes are especially vulnerable.

Ants are particularly fond of this honeydew, “milking” the aphids and taking it back to their nests. In return, ants fend off predators such as ladybeetles and parasitoid wasps and reduce fungal diseases by removing infected bodies. One experiment conducted in Japan blocked ants from tending eight aphid colonies; all the colonies perished except for a lone survivor in one colony; the others were all eaten by natural enemies!

To keep ants out of trees, place sticky tape (e.g. Tanglefoot) around the trunk to trap them. Be sure to prune back other access routes such as where branches contact the roof, fences, or other plants. Check the sticky tape regularly, as dead ants stuck on the tape can create a morbid, but functional bridge to the other side for their living counterparts.

Sticky tape works best on single-trunk trees. For everything else, use a bait station with slow-acting poison to manage ant populations. Foraging ants collect the bait and take it back to their colony to share death with everyone, including the queen. For minor ant issues, ant stakes or small bait containers will do. For serious invasions, refillable bait station may be necessary. When selecting a bait, remember that ants are attracted to various foods depending on their species and the time of year. Baits are generally carbohydrate, protein, or fat-based; if ant identification eludes you, try different products to see which they prefer. Consult the UC Integrated Pest Managament page on ants to see who likes what: <>

Besides shooing the ants away, you can encourage their natural enemies to take up permanent residence in your outdoor home, providing faster relief for your plants. Avoid using broad spectrum pesticides, which kill everything (pests will always return first if predators are gone). You can also provide nectar plants for the beneficials, which need food when aphids are not around. Aphids predators are small, so their forage should be correspondingly small. Asters, Yarrow, Buckwheat, and Coreopsis are all good choices. Provide water by lightly sprinkling plants in the morning.

You can also create a less hospitable home for aphids. Avoid overwatering and high applications of nitrogen fertilizer, which causes plants to put out a lot of lush growth that aphids love. Aphids can be knocked off plants with a spray of water; infested plant parts can also be pruned off. If you absolutely must use a chemical, try neem oil or insecticidal soap, which have a short residual time and are less likely to kill non-target organisms (i.e. beneficials) than broad-spectrum pesticides. Thorough coverage of the foliage is necessary for good control, and repeat application may be needed until populations are tolerable.

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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Sages are great perennials in your border

Perennial borders are wonderful. Little or no annual planting, but some pruning and deadheading required from time to time to keep plants flowering. Sage advice is to include some sage plants, in your perennial flower bed. The true sages are Salvias, but Russian sage, Perovskia atriplicifolia, is not a true sage, nor is it from Russia, but it is also a great plant for the border. It is a non-stop bloomer that is easy to care for, with fragrant blue flowers that can attract bees.

I dug up a small seedling several years ago from a garden club friend and since then have multiplied it a few times in my landscape and have dug a few gift plants for friends. It does go to seed and is easily propagated, but it is not uncontrollable or obnoxiously invasive. Since it can get 5 ft tall, near the back of the border may be the best spot. It requires well drained average soil, full sun and moderate water. It is drought and heat tolerant.

I am unsure which cultivar I have, but Russian sage cultivars include ‘Blue Mist’, which has light blue flowers, ‘Blue Haze’, ‘Blue Spire’, which have deep purple flowers, ‘Longin’ a lavender-blue, with stiff upright stems and a more formal appearance,  ‘Little Spire’, a dwarf variety (2ft. height), and ‘Filigran’, a cut leaf, lacier texture with more upright growth.

Salvias come in a wide palette of colors and sizes and have a long bloom season. I especially like the dark violet-purple, 30 inch tall, Salvia nemorosa‘Caradonna’ cultivar which blooms from May to October if deadheaded after the first bloom. It was awarded the most Outstanding New Perennial in 2000 by the International Hardy Plant Union. ‘Caradonna’ attracts butterflies, bees, and hummingbirds and is rabbit/deer-resistant as are most Salvias.  It is all the more striking when planted with yellow flowering companions such as the daylily, ‘Stella d’ora’, Coreopsis ‘Moonbeam’, or yarrow, Acheillea ‘Moonshine’.

Salvia nemorosa 'Caradonna' provides a purple addition to the perennial border. Photo by Lee Miller

I also like and have grown Salvia x sylvestris ‘May Night’ hybrid which is also indigo blue flowered with a height of 18 to 24 inches. It is increased by division as this is a sterile hybrid.

Salvia greggii, Autumn sage, is an American native that is mostly red blooming in the wild and comes in a variety of mostly red cultivars, but also in orange, pink, white, blue depending on the region it is from. The range of colors has been enhanced by breeding new cultivars. It is disease and insect free and drought tolerant.  It is a great plant for our drought prone area. I have to admit I was curious about how this Salvia acquired the name greggii. I found out that it was named by botanist, Asa Gray in 1870, in honor of Josiah Greg, a southwest explorer and naturalist who discovered it in Texas in the 1840’s. He died at age 44, falling off a horse in 1850, so honored he is, with this appreciated plant.

Salvia greggii should be lightly pruned periodically during the summer and it should be taken back to about a third of its size in February just before the growth season. This will keep the plant healthier looking going into spring.

Another species with several cultivars is Mexican sage, Salvia microphylla. ‘Hot Lips’ is a cultivar that is commonly planted and it is a large plant that gets 30 inches tall and sprawls 6 feet.

Salvia 'Hot Lips' is a colorful addition to the border. Photo by Lee Miller

It is adorned with stunning bicolor flowers with red tips and white lips. In spring, the first flowers are all red, then bicolor.

Mexican Bush Sage, Salvia leucanthea, which is a 40 inch tall bush with purple and white velvety flowers that blooms from late summer to fall. It is cold hardy in our zone and well worth having if you have room for it.

For a run down on the many kinds of Salvias available see: , or  Here is to being sage and add some sages to your landscape for long flowering beauty with less watering.

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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Watch what and where you plant!

I see so many plants that are planted in the wrong place for the size of the plant. ‘Wrong plant wrong place’ perhaps, instead of ‘right plant for the right place’ as our gardening mantra goes. By right plant in the right place we should take into account not only the environmental conditions that the particular plant needs, such as soil, light, moisture, hardiness, etc, but also the eventual size that it will become and its future impact on our gardening activities.

The problem is that when we purchase plants they are so small; it may be hard to visualize how large they might become someday. I live in a Victorian home built about 1895 and the builder was an amateur horticulturist, so he planted a variety of plants which included a horse chestnut (Aesculus hippocastanum).  It was planted about 10 feet from the house and now it towers about 60 feet with branches touching the roof and hovering over it. Definitely it is a problem of being too close to a structure, a not uncommon problem in landscapes.

Horse chestnut planted too close to the home and Cotoneasters too tall for foundation plantings.

Recently I looked at a property that had two large conifers, a Deodor Cedar (Cedrus deodara) and an incense cedar (Calocedrus decurrens), planted only about 10 feet apart. When planted as small trees in the 1950’s that distance likely looked very large. However, now that both trees are over 50 feet tall, with interlocking branches shading out lower limbs, the distance apart was obviously too small. One tree needs to go, if not both of them and the expensive removal costs will not be paid by the person who planted them.

In surveying my own landscape I can find mistakes too. I planted a Chinese fringe shrub (Loropetalum chinense) several years ago and I thought it would grow only 3 feet tall as per my observations of other specimens in people’s landscapes. According to the specifications for the species it can get over 6 feet tall, so I obviously did not do my homework. It is now 5 feet tall and blocks one of my sprinklers. I added 12 inches to the sprinkler riser, but that only helped for one year. Now the sprinkler is blocked again, so it’s time for serious pruning to reduce it in size. Had I checked out the mature size before planting, I would have found a different spot. The good news is that Lorapetalum tolerates heavy pruning, but the bad news is it will likely need doing often.

Another mistake I made was planting Salvia microphylla ‘Hot lips’ too close to a walkway. If I had read up on this prolifically blooming plant, I would have learned that it can sprawl 6 feet, so planting it 1.5 feet from the walkway was only half way from where I should have put it. It is a beautiful plant, but now I need to prune it to keep it in check.

Foundation plants around homes can be another area where size can be a problem. At my home,   Cotoneasters that grow to over15 feet were planted along the west side of the home and two Camellias, 20 feet tall, are on the east side. Both of these plantings block the view from the windows which in my case is not a big problem. Because I don’t have air conditioning they do tend to shade the home and keep it cooler. When selecting foundation plantings, it is wise to look for plants that will not block views or become crowded.

Being aware of is the aggressive plants can also prevent a lot of work. I planted a New England aster which blooms with blue flowers in the fall and attracts butterflies and other beneficial insects. However, it is very spreading in habit with underground rhizomes spreading the plant in a widening circle. I took it out and put it in a 15 gallon pot to contain it, but 5 years later I still have remnants popping up among my Iris and though I dig them out each year, I never have defeated this plant as it pops up again the next year.

Similarly, a past owner had planted periwinkle, Vinca major, which has become a major pain in my horticulture. I have been trying for forty years to get rid of it without success. If I let up on extermination efforts, I soon lose what gains were made because it is aggressively invasive.  
Avoid ‘wrong plant for the wrong place’ by checking the label before you plant or consult a ‘plant finder’ website such as: or Sunset’s Western Garden book on the plant to find out its maximum size. For information on noninvasive alternatives to invasive plants consult May all your plantings have happy endings.

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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Bee Kind to Our Hardworking Pollinators

Master Gardeners are often asked to speak at local garden clubs and other social organizations and a topic that is always of interest is gardening for pollinators, especially bees.  It seems lately, gardeners are trying to do their part in helping the bees, and that is a good thing!

Native bumble bee. Photo credit: Kathy Keatley Garvey

There are 4,000 species of native bees in the country. Some are social and some are solitary. There are specialistbees and generalist bees. These bees pollinate approximately 75 percent of the fruits, nuts, and vegetables grown in this country and 80 percent of our flowering plants. Most people are familiar with the European honey bee (originally from South and Southeast Asia), but few know that California is home to 1,600 species of native bees, the most diverse bee population in the U.S..

According to the Xerces Society, native bees are North America’s most important group of pollinators. California’s native bees pollinate our crops yet they don’t make a drop of honey for human consumption.  They are 200 times more efficient at pollination than honey bees! According to the National Sustainable Agriculture Information Service, pollinating an acre of apples requires 60,000-120,000 honey bees; the same area can be pollinated by 250-750 mason bees.

Some of the more common families of bees found in CA are:

APIDAE (Cuckoo, Digger, Carpenter, Bumble, and Honey Bees) The family Apidae is very diverse and is the largest group of bees. It contains a diverse array of digger bees, most of which nest in the soil, carpenter bees which nest in soft wood or pithy stems, and bumble and honey bees which nest in large cavities or hives, are social, and have distinctive pollen baskets

COLLETIDAE (Membrane Bees) The small family Colletidae is known for the membranous, cellophane-like secretions used by females to line burrows they excavate in the soil, or that they construct in tubular cavities.

ANDRENIDAE (Mining Bees) This is a large family of soil nesting bees, hence the common name Mining Bees. These are among the first bees to emerge and visit flowers in spring.

HALICTIDAE (Sweat Bees) Sweat bees have earned their common name from the tendency, especially of the smaller species, to land on ones skin and lap up perspiration for both its moisture and salt content.

MEGACHILIDAE(Leafcutting, Mason, Cotton Bees) The family Megachilidae is a large and diverse group of bees. They are the architects of the bee world. They nest

Male valley carpenter bee. Photo credit: Kathy Keatley Garvey

primarily in pre-formed tubular cavities (tunnels of woodboring beetles, hollow plant stems, and even abandoned snail shells) using a wide variety of materials collected from the environment, including leaf and flower pieces, masticated leaves, mud, resin, plant hairs, and pebbles to construct brood chambers for their young.

You can help California’s hardworking bees by making a few simple changes in your garden. Here are some helpful tips to keep in mind as you grow your bee-friendly garden.

Provide Food One of the best ways to initially attract wildlife to your garden is to provide food. In the case of bees it’s with flowers that provide nectar and pollen all year long. Adult bees feed on sugary nectar for energy. The pollen they collect is a protein and vitamin rich source which they will feed to their young.

If you have the space, plant flowers in patches. These provide more resources and allow bees to forage in one spot for a long period of time. As well as having large patch sizes of flowers, diversity is also important. Native bees are more likely to forage on native plants, so the more diversity of plants the better. Bees are attracted to brightly colored flowers in shades of blue or yellow (bees cannot see red) that are open during the day. Try to avoid hybridized plant varieties, as they are often less beneficial for bees

Provide Cover and Places to Raise Young Most native bees are solitary nest makers and between 60-70% of the native CA bee species dig tunnels in soil and create a series of nest cells. If you are a “mulcher” make sure to leave some bare dirt areas because bees will not dig through a thick layer of mulch.

Provide Water Water is also a key resource for wildlife and bees are no exception. Bees need a place to get fresh, clean water. Fill a shallow container of water with pebbles or twigs for the bees to land on while drinking.  Make sure to maintain the container full of fresh water to ensure that they know they can return to the same spot every day.

Reduce pesticide use. It is extremely important to avoid using any insecticides, herbicides, or pesticides on your plants – even organic ones contain substances that are harmful to bees.  Pesticides do not distinguish between pests and pollinators. If you must use a pesticide, use the least toxic material possible. Before purchasing, read labels carefully, as many pesticides are especially dangerous for bees. Never spray a blooming plant and spray after dusk when bees and other pollinators are less active.

By adding a few easy to do features in your garden you can provide an oasis for local bees.  In return, the bees will pollinate your flowers, providing a bountiful harvest of fruits, seeds and vegetables as well as the joy of watching them up close.

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




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It’s Time to Thin Fruit

Spring is a busy time in the garden and gardeners often find themselves with a list chores to complete. If you are looking for some inspiration to get started in your own garden, join us at our Spring Open Garden day on April 22, from 9 am – noon.  Master Gardeners will be working in the garden and will be available to answer your gardening questions. We will have tomato plants for sale, several displays and demos (including tool sharpening so bring your pruners) and light refreshments. Come on out so you can see how to complete some of these spring garden chores. The garden is located at 2101 E Earhart Ave, Stockton, 95206. If you would like to see pictures from our Fall Open Garden day, click here.

By now, spring fever shopping at the local nursery has lead to a car full of plants that still need a home in your yard, the weeds are abundant, the battle with the aphids is beginning and we can’t forget the planning and planting of summer vegetable gardens. Your fruit tree should be loaded with small fruit and I bet you can already taste that ripe, juicy peach on a hot summer day.

 One of the most often overlooked chores is fruit thinning. Fruit trees often set more fruit than they can support, especially if the trees were not properly pruned during the previous season. Excessive fruit compete with each other for carbohydrates (stored energy) and remain small.


Thinning immature fruit at the appropriate time allows each remaining fruit to develop to its maximum size. Less-crowded fruit receive more sunlight, so fruit color and flavor may be improved.

Reducing the fruit load through proper pruning and fruit thinning, especially near the ends of branches, lessens the chances of limb breakage. It’s much less tragic to pluck many tiny peaches off your favorite tree than to lose an entire limb because it was so heavily weighed down. It can also reduce alternate bearing (a cycle in which the tree bears excessively in one year and little the next year).

Fruit thinning can also reduce the spread of some diseases. For example, if the fruit are touching each other, brown rot can quickly spread from one fruit to another just before harvest.


Flowers and fruits naturally thin themselves, often at distinct time periods. Blossoms that were not pollinated turn yellow and drop off just after flowering. Small, immature fruits often drop naturally during what is known as “June drop,” which usually occurs in May in California. Fruits that are diseased or infested with insects may also drop prematurely.


Cherries, figs, persimmons, pomegranates, citrus, and nut trees do not usually require thinning. However, branches of persimmon trees can break from the weight of a heavy crop and may benefit from some fruit thinning or branch propping. All stone fruits (peaches, apricots, nectarines, cherries, plums, etc.) require thinning. Pome fruits like apples and Asian pears as well as most European pears require thinning. Bartlett pears often thin themselves, and harvesting larger fruit early (early to mid-July) allows the smaller fruit to increase in size for a second pick 1 to 2 weeks later.


Fruit should be thinned when they are fairly small–typically from early April (for early-ripening fruit) to mid-May (for late-ripening fruit). The amount of fruit to thin depends on the species and the overall fruit load on the tree. For example, stone fruits such as apricots and plums are fairly small, so they should be thinned to 2 to 4 inches apart on the branch. Peaches and nectarines should be thinned to about 3 to 5 inches. When the crop is heavy, fruit should be spaced no less than 6 to 8 inches apart.

Unlike stone fruits, which produce one fruit per bud, pome fruits (apples and pears) produce a cluster of flowers and fruit from each bud. Thin to no more than one to two fruit per cluster, depending on the total fruit set and growing conditions


It’s a simple (but tedious) task to thin fruit and it doesn’t require any special equipment, all you need is your hands. To avoid damaging branches, twist fruit off gently rather than pulling it. Remove “doubles” (two fruit fused together) and small, disfigured, or damaged fruit when you have the option. Extremely small or damaged fruit should be removed regardless of spacing, and leaving the largest fruits on the tree is more important than exact spacing. So, you will have to use your own judgment when making decisions about which fruit to thin and which to leave.  Keep the largest fruit whenever possible.

If thinning by hand is impractical you can use a pole to help with the process. Pole-thinning is much faster, and although it is less accurate, the results are often sufficient. Attach a short rubber hose, cloth, or thick tape to the end of the pole to reduce scarring or bruising of branches. Strike individual fruit or clusters to remove a portion of the fruit. With experience, you will be able to strike a cluster once or twice with just enough force to adequately break up the cluster.

Once you have experienced the fruit at its best, thinning is performed with a solid sense of purpose and maybe even some excitement.

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



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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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  • 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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