Things to do in June
Advice at the Fair

Viewing the display gardens at the San Diego County Fair is bound to spark questions about what’s growing there – or in your home gardens. Luckily, there’s plenty of good free advice available from many horticultural groups that staff booths there.  San Diego County Master Gardeners will staff a booth where they will answer questions and hand out free pest control information. Volunteer experts also are available daily in front of the San Diego Horticultural Society display. In addition, experts appear on the Flower Show Stage for talks on a wide range of gardening topics. For a complete schedule, visit

Apply nitrogen fertilizer
Apply nitrogen fertilizer to warm-season crops to promote growth. fertilize when corn is six inches tall and 24 inches tall; when cucurbits begin to produce runners; when eggplant, peppers and tomatoes begin to bloom (and again a month later); and beans – one month after planting or when runners start to climb. Feed with nitrogen fertilizer for every 10 feet of row, apply one-third to one-half cup of ammonium sulfate or one-fourth cup of ammonium nitrate alongside the row a few inches from the plants and then irrigate thoroughly.
Be a Deadhead Fan

In San Diego's mild climate, many annuals and perennials will bloom again with just a little help from gardeners. A key step is deadheading or removing spent flowers. When left on the plant, they send a signal for the plant to set seed and either rest or end its lifecycle. When they are removed, the plant is tricked into overdrive to produce more flowers. On some plants, use your fingers to snap off stems with dead flowers. On plants with many small flowers, like daisies, dead flowers can be removed by giving the plant a "haircut" with sheers or loppers. If the foliage is ratty, cutting back by a third or a half will renew it too. On plants that may be woody at the base, like lavender, avoid cutting back into the wood. After deadheading, a light feeding helps spark new growth.

Care for Fruit Trees
Irrigate all fruit trees thoroughly as needed to maintain adequate soil moisture. Apply water around mature trees in a broad band beginning one-third of the distance from the trunk to the tree's drip line and extending out beyond the drip line a few feet. Apply enough water to wet the soil at least two feet deep. Remove grass and weeds from soil under the tree's canopy and then add a layer of coarse organic mulch to conserve moisture. Keep mulch at least one foot away from the trunk to protect trees from crown rot. During the summer, wash trees periodically with a forceful spray of water to remove dust, honeydew and pests like aphids, whiteflies and spider mites.
Check citrus for Diaprepes Weevil
Check citrus and other woody plants of diaprepes root weevil for semi-circular notches along the edges of new leaves. For photos and quarantine information see and enter diaprepes in search box. Call 800.491.1899 to report possible infestation.
Check for Citrus Pests
Check citrus and other hosts of diaprepes root weevil for semi-circular notches along the edges of new leaves. For photos and information, visit and type diaprepes root weevil in the search box. Also examine new "flush" growth for signs of Asian citrus psyllid. This insect can spread a fatal citrus disease that has been discovered in a tree in the Los Angeles area. Visit for more information. If you think your citrus tree is infested with the psyllid, report it by calling the exotic pest hotline at (800) 491-1899.
Check vegetables for pests
Check plants for pests. Spray or dust tomatoes lightly with sulfur when plants are one-foot tall to control russet mites and powdery mildew. Wrap paper collars around the stems of tomato transplants when planted to protect from cutworms.
Combat Aphids
The British call these soft-bodied pests “plant lice,” a sign of how ubiquitous they are in gardens. Often the color of their host plant, they suck juices from tender leaves and stems, distorting them and weakening the plant. More often than not, aphids are aided and abetted by ants that “farm” (tend and protect) them for the honeydew they secrete. Fortunately non-chemical controls are remarkably effective. Start by dislodging the bugs with a blast of water or flick of the finger. (The non-squeamish can squash them between their fingers for instant gratification.) Then control ants using “ant motels” that let foraging ants take pesticide home to ultimately destroy the hill. If aphids are in citrus and other trees, a trunk barrier like Tanglefoot spread on a protective collar can help keep ants out of the tree. Avoid the use of broad-spectrum pesticides since aphids have plenty of natural enemies that could be wiped out as well. More information is at
Control ants
Control ants, which protect aphids and other sap-feeding insects; visit for Pest Notes on Ants and other garden problems.
Deadhead Roses

'Julia Child'

Enjoy the beauty of blooming roses now through October with a few easy steps, starting this month when spring's first bloom peaks and ebbs. Start by cutting roses either while they are in full bloom to perfume your home or when they are spent and no longer adding beauty to the garden. Both steps are a kind of pruning that will stimulate new blooms. As a rule of thumb, make the cut above a growth node at a five-leaflet leaf pointing outward at a mid-way point on the cane. Cut too high on the cane and the new roses will have weak stems; too low a cut will slow rebloom and may result in an unsightly plant. Feed lightly with an organic or all purpose fertilizer and water deeply. Repeat after each bloom cycle to keep roses flourishing - and flowering in the months ahead.
Do Deadhead

To keep gardens tidy and flower-filled, devote time weekly to cutting off spent blooms. Left on, they signal the plant to set seed and either die or go dormant. Removed, they encourage perennials and annuals to produce more flowers. With some plants like roses, the faded flowers are trimmed one at a time. Other plants, like osteospermum, coreopsis and lavender, get “a haircut,” a snip across the top and sides with hedge shears. Generally these deadheading cuts aren’t as deep as pruning, but in all cases, they avoid cutting into woody stems.

Feed Vegetable Plants
Fast-growing vegetables need regular feedings of nitrogen to thrive. For every 10 feet of row, apply one-third to one-half cup of ammonium sulfate or one-fourth cup of ammonium nitrate alongside the row a few inches from the plants and then irrigate thoroughly. Apply when corn is six inches tall and then again when it is 24 inches tall; when cucurbits begin to produce runners; when eggplant, peppers and tomatoes begin to bloom and again one month later; and for beans, a month after planting or when runners start to climb.
Fight Powdery Mildew

Overcast days and humid conditions are ideal for powdery mildew, the fungal disease that coats leaves and stems of susceptible plants with dirty-white “fur.” In time, the unsightly fungus stunts growth and blooms. Though it may seem counterintuitive, spraying plants daily with a jet of water early in the day can reduce the spread by eliminating the dry surfaces required by the disease-carrying spores to germinate. On lightly infected plants, remove and dispose of infected leaves. Good air circulation between plants also helps keep the fungus at bay. Fungicides including non-toxic horticultural oils can slow mildew's spread but rarely eliminate it. In recent years, breeders have developed new varieties resistant to mildew and other diseases. Check labels of particularly sensitive plants like roses before you buy.  Learn more about this and other fungal diseases at

Fighting Eugenia Psyllids

Spring weather is a boon for garden pests, many of which have been inactive in the previous cool months. Some like the psyllids that attack Eugenia hedges or eucalyptus trees appear before their natural predators make their seasonal comeback. Be patient while waiting for their enemies to reduce psyllid populations and the damage they do. Eugenia hedges can be sheared every 6 weeks to remove new foliage damaged by the Eugenia psyllid. Leave the clippings around the base of the plant to allow time for tiny beneficial wasps that attack psyllid larvae to emerge. Do not feed plants with nitrogen fertilizer in spring since lush, new growth favors psyllids.

Fruit Drop
Don’t despair if citrus or stone fruit trees drop tiny lemons, peaches and nectarines this month. This is Mother Nature’s natural pruning that rids the tree of over abundance and focuses its energy on fewer fruit. The result is a larger and more flavorful crop. If you would like an even smaller crop, pick off baby fruit where there are multiples, leaving just one to continue growing. Space peaches and nectarines 4-6 inches apart to increase fruit size and prevent limb breakage. Clean up the fallen fruit to keep pests and animals away. One caution: While fruit drop occurs naturally, a dramatic loss of immature fruit could be the result of water stress. Be sure fruit trees receive several deep waterings this month and next and don’t allow them to dry out for extended periods.
Gardenia Savvy

Their creamy petals and potent perfume make gardenias a favorite wedding flower. Gardeners, though, often are wary of gardenias in the landscape because of their finicky reputation. To succeed with these plants, be sure to buy varieties on grafted root stock. When classic Gardenia augusta (formerly G. jasminoides) varieties like ‘Veitchii,’ ‘Mystery,’ and ‘White Gem’ are grafted on to root stock of G. thunbergia, the plants are more tolerant of our alkaline soil and water. Tags will say if the plant is grafted. Also expect to pay more for grafted plants. Locate gardenias is bright shade, keep evenly moist but not wet and feed regularly with an acid plant formula, especially if container grown. G. thunbergia, when not grafted, grows into a large shrub or small tree with beautiful blooms in winter.

Get Landscape Design Advice
Shocked by high water bills? Determined to transform your garden into a waterwise landscape but not sure where to begin? Jump-start your makeover with a professional landscape design consultation at The Water Conservation Garden. The 45-minute sessions are with consultants who specialize in drought-tolerant landscapes. Homeowners bring photos and dimensions of a targeted area; they leave with a design plan and plant list. Cost is $75 ($60 for garden members). Call (619) 660-0614, ext. 10, to learn dates and availability.
Go Bananas

Of the 1,000 banana varieties in the world, only one tends to show up in supermarkets. Luckily these handsome broad-leafed plants thrive here in frost-free areas, giving San Diego gardeners a chance to savor homegrown fruit, some with tasty overtones of apple, mango or papaya. Master Gardener Carol Graham, a banana expert, suggests "cold-hardy” ‘Orinoco’ grown in California for decades, Honduran-bred ‘Sweetheart’, ‘Cardaba’ ideal for cooking, and ‘Cuban Red’, one of the exotic red-skinned varieties. Plant them in full-sun and provide regular water in well-draining soil. Wind damage to leaves- think of it as fringe, Graham says - won’t inhibit fruiting which generally occurs within two years after planting. For more information and retail sources, visit the web site of the California Rare Fruit Growers,, or their booth at the San Diego County Fair.

Grow Dazzling Dahlias

Native to Mexico and Guatemala, dahlias have captivated plant lovers for centuries starting with Spanish explorers in the 1600s. Robust dahlia plants bear striking flowers ranging from golf-ball size pompoms to daisy-like collarettes. Choosing among the 50,000 named varieties can be daunting. Below are selections from Sharon and David Tooley, award-winning Penasquitos dahlia growers active in the San Diego County Dahlia Society.

Jessica - Striking cactus-type flowers with narrow incurved (rolled under) lemon yellow petals tipped in vivid magenta-red. Four to 6-inch wide flowers on 3-4-foot tall plant.
Penhill Watermelon - Flowers up to 10-inches wide are among the largest grown. Gracefully curved petals are blushed with cream, rosy pink and golden yellow.
Zorro - Another 10-inch wide whopper with deep red ruffled petals. Stems are strong, but this and other large-flowered plants may need staking.
Pam Howden - A waterlily dahlia with symmetrical petals that curve gently inward. Orange, pink and yellow petals create a sunny glow.
Chimacum Troy - A mini-ball type dahlia with 3-inch round flowers in rich purple-red. Plant grows about 3 feet tall.
Alpen Diamond - A colarette dahlia with eight petals surrounding a central raised cluster of smaller petals. Outer petals are pink, lavender and white with center petals of golden orange.

Two of the Tooleys' favorite sources are Colorado's Arrowhead Dahlias ( for tubers and Corralitos Gardens ( on California's Central coast for rooted cuttings.

Grow Flowers Good Enough to Eat

Trendy restaurants sprinkle them on salads or use them to garnish deserts. Gardeners can do the same by growing some edible flowers. Most are easy to cultivate and have multiple uses in the kitchen. Be forewarned, says Rosalind Creasy, author of "Edible Flower Gardening," not all flowers are edible, and some like oleander are poisonous, so stick with tried-and-true options like those below. If you have allergies or asthma, begin by consuming only small quantities.

Calendula (Calendula officinalis) - While not the most flavorful, the fresh golden petals of this old-fashioned annual brighten salads or omelets. This Mediterranean native likes full sun and moderate water.

Chamomile (Matricaria recutita) - The petals of chamomile’s dainty daisy flowers add a pineapple flavor to hot or iced teas. Dried, they make the classic chamomile herbal tea. This attractive plant with ferny foliage prefers full sun.


Borage (Borago officinalis) - Borage’s starry petals have a cucumber flavor, making them an ideal salad garnish. Remove the fuzzy stamens before adding to your favorite greens. Grows to 3 feet tall and tolerates poor soil and low water. Full sun.


Nasturtium (Tropaeolum majus) - A chef favorite for their hot color and spicy bite, nasturtium blossoms  and leaves can be chopped and tossed “like confetti,” Creasy says, over salads. Also use them to flavor butters, oils, vinegars and soft cheeses. This spring bloomer likes sun to part shade and regular water. Reseeds vigorously.


Squash blossoms (Curcurbita spp.) - Sweet squash blossoms are a farmer’s market favorite among cooks who stuff them with meat or cheese mixtures. If you’re growing zucchini, reduce your crop by harvesting blossoms. Remove stamens and pistils before using. Plant this warm-season vegetable now.


Johnny-Jump-Ups, Pansies and Violets (Viola cornuta, V. tricolor, V. wittrokiana and V. odurata) - Pretty single or multi-colored flowers in shades of blue and purple sparkle in salads. Ambitious cooks can candy blossoms to accent desserts. Plant in early winter for spring bloom and give regular water.


Grow Lemons in Containers

Pictures of classic Italian gardens almost always show a row of container-planted lemon trees. To duplicate that look - or add a single lemon or other citrus tree to a small patio or balcony, start with the right size pot - a container taller than it is wide and one size larger than the nursery pot the tree came in. A 50-50 mix of quality potting soil and an azalea or other acid-plant soil mix will help the tree thrive. Pick a healthy tree - one with healthy leaves and new growth, plant it in the container, and water thoroughly. Water regularly thereafter when the top one or two inches of soil is dry


Grow More Veggies

Tomato 'Aussie'

More urban farmers tend tomatoes than any other vegetable. But there are many other vegetables and herbs to try during San Diego's warm growing season. Add the classic Genovese-type basil and some sweet bell peppers for a pizza garden. Handsome eggplant plants bear pretty lavender flowers as well as colorful fruit, while a couple zucchini plants handily feed a family all summer. If space is available, plant an artichoke with its dramatic silvery leaves on a plant that can soar to 4 feet or more tall and wide. Explore more options in the Master Gardeners' cool and warm season vegetable planting guide that also includes recommended planting times along the coast and inland. Visit and click on Resources. Another good guide is "Sunset Western Garden Book of Edibles."

Grow Waterwise Edibles

Many fruit trees and veggies need substantial water to thrive – but not all. Here are some favorites:

  • Jujube or Chinese date (Zizyphus jujube) – This handsome deciduous tree bears sweet apple-flavored fruit that can be eaten off the tree or dried, when they resemble dates. Grows to 30 feet tall, but can be pruned to maintain a height of 8 to 10 feet.
  • Mulberry – Blackberry-like fruit without the seeds on a tree with no thorns – yum. Look for 7-inch long fruit on ‘Pakistani’ (Murus sp. ‘Pakistani’); smaller spicy berries on Black Persian (Murus nigra). These deciduous trees have expansive canopies and roots and the fruit can stain hardscape. Plant in an open area..
  • Pineapple Guava (Acca sellowiana or Feijoa sellowiana) – This versatile South American native can be grown as an espalier, tree or privacy hedge. Silver-backed glossy green leaves highlight white flowers with red stamens and gray-green fruits that follow. Both fruits and flowers are edible. Evergreen.
  • Artichoke (Cynara cardunculus) - Delicious flower buds are the edible part of this Mediterranean native. If not picked, the buds open into purple thistle-like flowers, handsome complements to the dramatic silvery foliage below. Grows to 3 feet or more, tall and wide. Self-seeds.
  • Pomegranate (Punica granatum) – Yetz grows more than 2 dozen varieties of these showy deciduous trees for their attractive tasty fruits. One favorite is ‘Pink Ice’ with softer seeds and sweeter pulp than found in the popular ‘Wonderful.’ Emerging foliage is bronzy; in fall, leaves turn gold. Prune to keep height around 10 to 15 feet.
  • Jojoba (Simmondsia chinensis) - Yetz loves to eat the nuts from this California native roasted and salted.  Evergreen with silvery green leaves, this shrub grow to 5 feet tall. Heat loving. Nuts are easy to shell.
  • Goji berry (Lycium barbarum ‘Goji’) – One of the new “power-fruit” sources of anti-oxidants, goji berries thrive here. Sprawling shrub with slender gray-green leaves bears red berries that are “sweeter than a cranberry but not as sweet as a cherry,” Yetz says. Grow to 5 feet tall; prune to keep compact.

More information on many of these plants is available on the CRFG web site,

Grow Worldly Vegetables

Grow Worldly Vegetables
Gardeners who love to cook now can grow classic ingredients for ethnic dishes, thanks to companies that are importing seeds from around the world. Here are three sources for gourmet kitchen gardeners.

  • Seeds From Italy – This one-man Massachusetts firm is the U.S. mail-order source for Franchi Seeds, one of Italy’s oldest seed companies. Franchi’s heirloom seeds are “what nonna used to grow,” says Seeds of Italy owner Bill McKay. His biggest sellers are Genovese basil, San Marzano tomatoes, zucchini and other squashes, and spring greens like agretti and dandelions. Garlic bulbs, mushroom kits, annual flower seeds and regional collections also are for sale. Order online at
  • Kitazawa Seeds – Located in Oakland, Kitazawa has been selling Asian vegetable seeds since 1917. Founded to help Japanese Americans grow ingredients for traditional meals, the company has branched out to include seeds for Thai, Vietnamese, Chinese and Indian vegetables. Discriminating Asian cooks can choose among 10 kinds of beans and 18 varieties of bok choy and eggplant, as well as more unusual finds like spicy leafed perilla or Chinese leek. Order online at
John Scheepers Kitchen Garden Seeds – This Connecticut-based company scours the world for seeds for varieties needed for ethnic and specialty dishes. Fans of pickling cornichons will find them here, along with other French favorites like Soleil Filet and Roc d’Or bush beans, breakfast radishes and Petit Pois (peas). The range and depth of vegetables from other countries is equally strong. Seed collections like the French, Italian or Mexican Garden, also are available. Order online at, where you’ll also find growing instructions and recipes.


Irrigate thoroughly as needed to maintain adequate soil moisture. Apply water around mature trees in a broad band beginning one-third of the distance from the trunk to the tree's drip line and extending out beyond the drip line a few feet. Apply enough water to wet the soil at least two feet deep (about three inches of water on a loam soil).
Mildew Dos and Don’ts

Most rose growers have grappled with powdery mildew, a fungus that coats leaves, stems, buds and fruit with a dingy white growth that disfigures and debilitates them. But this pervasive disease affects plants ranging from sycamores and crape myrtles to grapes and squash, dahlias and zinnias. The fungus thrives in the moderate temperatures and humid air prevalent during June gloom. But oddly enough, it needs a dry plant surface to become established. When the powdery white fungal growth first appears, spray affected leaves with a strong blast of water that destroys and dislodges spores. This is best done early in the day so plant surfaces dry before night. Frequent rinses will destroy mildew spores. Horticultural oils and fungicides appropriate for the affected plant also can be used following package directions. If mildew is an on-going problem, replace afflicted plants with resistant varieties and plant them where they will have plenty of air circulation and sunshine. For downloadable information on powdery mildew and other plant diseases, visit

Remove grass and weeds from soil under the tree's canopy. Apply a layer of coarse organic mulch on the soil under trees to conserve moisture. Keep mulch at least one foot away from trunk to protect trees from crown rot.
Mulch Madness
While days are still mild, and sometimes cooled by fog, take the time to add a fresh layer of mulch to growing grounds. Mulch is critical to plant health in the hot months ahead since it keeps roots cool and slows water evaporation from moist soil. It also is key to soil health because, as it decomposes, it replaces quickly depleted organic matter. Not all mulches are equally beneficial. Some, like sawdust, actually pull nitrogen from soils. Get shredded wood instead, the kind some tree trimmers will give for free. Compost also can be used as mulch. Dig some into the soil and then pile on more until there’s three inches on top of the bare soil (or last year’s mulch). Avoid putting mulch/compost up against tree trunks or the base of plants since it can cause rot and other problems. Also adjust irrigation to be certain water is penetrating the mulch to reach the soil and plant roots below.
Native Plant Care
Avoid transplanting natives during the summer; you will have more success in the fall. Most established native plants can go three to four weeks between watering, however natives planted earlier in the year will need additional supplemental water while they become established. Riparian natives that thrive in damp environments also will need regular watering once or twice a week.
Orchard Care

Most mature fruit trees need the equivalent of one pound of actual nitrogen annually. To calculate how much fertilizer you need, divide the percent nitrogen that the product contains into 100 (e.g. 100 divided by 20 percent nitrogen equals 5 pounds of fertilizer). Divide the amount of fertilizer into two or three equal lots and apply them six weeks apart once new growth begins. Because new growth is attractive to pests, check trees for aphids, spider mites and whiteflies. Wash trees periodically with a forceful spray of water to dislodge these pests. If a pesticide is needed, use a chemical that has a short residual activity, such as insecticidal soap, horticultural oil or pyrethrin, to protect beneficial insects. Because ants "farm" some insects, take steps to keep them off trees. Wrap a band of heavy paper or duct tape around the trunk and coat it with a sticky material like Tanglefoot. Trim branches that touch other objects to stop ants from going around the barrier. Also place ant stakes or containers with toxic bait by ant nests and trails.

Plant and Care for Oranges, Lemons and Limes

Start or add to your citrus orchard this month when conditions are generally ideal for planting. Oranges, lemons and limes thrive throughout the county; grapefruit and tangelos do best inland. Pick varieties hardy in your area and plant in full sun in well-draining soil. Dig a hole as deep as the root ball, but twice as wide to encourage wide ranging feeder roots that grow close to the ground's surface. After citrus is planted, proper irrigation is key. The root ball needs to be kept moist until roots grow out into the soil. But over watering can cause rot and other diseases. Start by watering at least once a week, more often in times of extreme heat or dryness. Increase the interval as the tree matures. As the trees grow new leaves or blossom, adequate regular watering also can help prevent leaf and blossom drop. Regular water too helps prevent fruit splitting in navel oranges that commonly occurs in fall. How to judge water needs? Check moisture levels about 2-inches below the surface. When dry to that depth, water again.

Plant Bromeliads

Bromeliads, with their handsome often mottled leaves and bold flower spikes, are prized houseplants, but in San Diego, these tropical perennials thrive outdoors as well.  About one-third of the 1,500 species are “air plants” or epiphytes that survive growing on rocks or trees. Others hold water in leaf-based “cups” in between rains or watering. Most tolerate low light and competition from tree roots, which makes them ideal for underplanting  in dry shade. One of the country’s major bromeliad growers, Kent’s Bromeliads, is based in Vista. To learn more about these plants, which include tillandsias, aechmeas, neoregelias, vrieseas, and desert-loving puyas, plan to attend the San Diego Bromeliad Society’s annual show and sale this month in Casa del Prado in Balboa Park.  Details are at

Plant Citrus with Cachet

May is ideal for adding to the citrus trees already perfuming your garden. If you already have lemon and orange trees, branch out with some exotics. Here are some to consider:

Blood orange (Citrus sinensis) - Fruit has red-blushed rind and ruby flesh with hints of raspberry flavor. Color is deepest in warm, dry areas. Available grafted on dwarf and standard root stock. Look for 'Moro,' 'Tarocco' and 'Sanguinelli.'


'Improved Meyer' Lemon (Citrus limon 'Meyer Improved') - Cooks like these juicy fruits that are thinner skinned and less acidic than 'Eureka' lemons. Often bears year-round. Grows to 12 feet tall on own root stock; 6 feet tall grafted on dwarf root stock.


Pummelo (Citrus maxima) - Fruit is like an oversized grapefruit in a puffy coat. Pink flesh is tangy. Needs less heat to fruit than grapefruit. Seedless 'Chandler' is a favorite. Grows to 15 feet tall on dwarf  rootstock.


Satsuma Mandarin orange (Citrus reticulata subsp. unshiu)  - Why settle for canned mandarins when you can pick them off your own tree?  These trees bear sweet, usually seedless fruit starting in late fall. 'Owari' is readily available. Grows to 6 feet tall on dwarf rootstock.


Kaffir lime (Citrus hystrix) - The distinctive hourglass-shaped leaves and lumpy rind of kaffir or kieffer limes add unmistakable flavor to Asian dishes. Grows well in containers on dwarf rootstock. Likes some humidity.


Buddha's Hand Citron (Citrus medica var. sarcodactylis) - A symbol of good fortune, these many “fingered” fruits are a cook's delight. Dry the fragrant rind for baking, grate it into salads, or add peel to flavor alcohol. Shrubby to 6 feet tall, it's an ideal container plant.


Plant these trees in the ground or containers now before summer's heat. Sprinkle granular fertilizer lightly on top of the soil and water well after planting. Keep soil moist but not wet during the first year as plants become established. For more citrus growing tips, click here to download a growing guide.

Plant Heat-Lovers
May is ideal for planting vegetables and annual flowers that thrive in the heat. Air temperatures are important - night-times should be consistently above 55 degrees F. And so are soil temps - the ground should be 65 to 70 degrees F. Together, with a sunny site, they provide a welcoming environment for edibles like tomatoes, peppers, melons, eggplant, corn, squash, cucumbers, basils and beans. Flowers happy with heat include cleome, cosmos, marigolds, zinnia, sunflowers, rudbeckia and nicotiana. Whether growing from seeds or seedlings, provide regular water as the plants become established; extra water if temperatures soar. Because these are fast-growers, regular feedings with a balanced fertilizer are a must.
Plant warm season crops
Plant warm-season crops, requiring warm weather and soil for rapid growth: beans, corn, cucurbits (cucumbers, gourds, luffas, melons, squash), peanuts, peppers, sunflowers, tomatoes and tender herbs (basil).
Prestige pumpkins

Cinderella's Carriage

Some are designer favorites - the so-called deep-lobed Cinderella pumpkins romanticized as the fairytale's magical coach and the mini pumpkins that dot tables at Thanksgiving.  Others are a cook's best friend - sweet pumpkins perfect for soups, pies and other holiday favorites. And some are a kid's delight - big orange orbs ideal for spooky carving. Now with Renee's Garden Seeds, all can be grown in home gardens. Order seeds now for "Cinderella's Carriage," baby "Mini Jacks," "Holiday Mix" of sugar and Jack ‘O Lantern pumpkins, and , if size matters, "Wyatt's Wonder"  to grow contest-worthy monsters up to 150 pounds. Packets are $2.79 each at Inland, plant these heat-lovers as early as late April, as soon as the days and soil warm. Along the coast, wait until mid-May or June.

Remove suckers
Remove any suckers growing from rootstock (below the graft union).
Rose Slug Remedies

There's no mistaking the toll of voracious rose slugs. Shiny new leaves are perforated with holes or stripped of green leaving behind a lacy brown skeleton. The culprit actually isn't a slug, but the larvae of sawflies, tiny wasps. Sawflies lay eggs on the underside of leaves and when they hatch, the larvae feed there. At the first sign of damage inspect leaves for the light green caterpillar-like larvae about 1/2-inch long.  For minor infestations caught early, remove affected leaves and crush any larvae. Larger numbers can be treated with strong sprays of water to the underside of leaves or a coating of horticultural oil, neem oil or insecticidal soap. None of these treatments harms bees or other beneficial insects. Because this is not a caterpillar, Bt (Bacillus thuringiensis) is not effective.

San Diego Gardeners' Companions "Sunset Western Garden Book"
Passionate gardeners are eagerly exploring the latest revision of the must-have "Sunset Western Garden Book," now for sale in soft or hardcover on line or in bookstores. This new 768-page edition is full-color and rich updated information on 9,000 plants. Plus there's a mobile edition of the Plant Finder.

The editors of this invaluable source book compiled an equally comprehensive guide (304 pages) of edibles for gardeners in California and the west. Information on when and how to grow some 250 varieties of herbs, vegetables and fruit is combined with advice on design, pest control and weed management. A paperback, the "Sunset Western Garden Book of Edibles" is also available on line or in stores.
Spray walnuts
Spray walnuts with carbaryl ("Sevin") when nuts are about the size of a nickel and again three weeks later to control coddling moth larvae (wormy nuts).
Stop watering onions
Stop watering onions and garlic grown for bulbs when leaves begin to turn yellow. Dig bulbs when tops have fallen over and place in a shady, well-ventilated area to cure.
Complete thinning apples, pears and stone fruit after "June drop."
Tomato Troubleshooting

It's frustrating when the leaves on your prized heirloom tomatoes turn yellow or are munched away by hungry worms. Here are explanations and help for some common tomato-growing problems.

  • Yellow leaves - Ozone and other air pollution can cause leaves to yellow. Some varieties are more susceptible to this damage than others. Experiment to find tomato varieties that will thrive in your garden.
  • Wilt and die - A healthy plant that suddenly wilts and dies is probably a victim of verticillium or fusarium wilt. Discard the dead plants and replant in a different area of the garden since these fungal diseases can live on in the soil. Also look for resistant varieties with the letters VF after the name.
  • Tomato hornworms - These large, striped worms often are spotted on stems or the backs of leaves. Pick them off or apply Bt (Bacillus thuringiensis) which is fatal to the worm but won't harm other beneficial insects. Look for it in nurseries or garden supply stores.
  •  Cracked fruit - Irregular irrigation generally is the culprit here. Water stress also can lead to blossom end rot that leaves leathery patches on the fruit. Water deeply in a 2-foot radius around each plant and increase irrigation when temperatures climb.
  • Blossom drop - Blossom loss occurs naturally when temperatures climb above 90 degrees during the day or drop below 55 degrees at night. When severe weather ends and temperatures adjust, healthy plants will blossom again and fruit production will resume.

Find a complete tomato growing guide on the San Diego Master Gardener Web site, The new "Sunset Western Garden Book of Edibles" also is a detailed source of problem-solving info.

Transition to Spring-Summer Annuals and Perennials

As gardens move toward spring's bountiful bloom, it's time to replace declining fall and winter blooming annuals with their spring and summer counterparts. Look in nurseries for six packs or 4-inch pots of colorful coleus, cosmos, verbena, marigolds, petunias, vinca, celosia, and other favorite annuals. Popular heat-loving perennials also can be planted now, including lavenders, kangaroo paws, sages, pincushion flowers (Scabiosa), asters, penstemons, heliotropes, artemisia and African daisies.

Troubleshoot Tomatoes

Strides in breeding have made tomato plants resistant to some debilitating diseases, thus increasing gardeners' success with them. But they are still prone to problems from pests, large and small. It may be hard to spot fat tomato horn worms but it's easy to defeat them with products containing Bt (Bacillus thuringiensis). Aphids and whiteflies can be blasted off vines with water or insecticidal soap spray. Russet mites, though, are too small to see without a magnifying glass, but they frequently are the cause of leaf death and drop on what seemingly are healthy plants. Sulfur dust or wettable powder is the best defense and treatment. Follow package directions to apply. 


Veggie Garden Tasks
The warming weather is ideal for planting warm-season crops: beans, corn, cucumbers, gourds, melons, squash, eggplant, peanuts, peppers, sunflowers and tomatoes. Also plant pumpkin seeds early this month for Halloween pumpkins. Herbs that like the heat, including basil, catnip and lemongrass, also can be planted now. Feed vegetable plants regularly with a nitrogen fertilizer and check daily for pests. Watch for powdery mildew on susceptible plants and treat with Serenade Garden when it first appears.
Visit website for more vegetable information
Visit for more information about growing vegetable crops.
Wash trees
Wash trees periodically with a forceful spray of water to remove dust, honeydew and pests like aphids, whiteflies and spider mites.