Things to do in April
Add New Plants to Your Garden

Got gaps in borders or beds? Fill them with some recent introductions, rather than settling for tried and true. Here are some options from some well-known growers. Look for these plants in area specialty nurseries or shop online sources.

From Proven Winners (www.provenwinners.com)



Blackberry Punch
'Blackberry Punch' and ‘Coralberry Punch' Superbells - These new Calibrachoas are the series' fashionistas. ‘Blackberry Punch' flowers are a sophisticated deep purple edged in magenta, while ‘Coralberry Punch' blooms have throats of rich burgundy. Easy to grow, long flowering and ideal for baskets and containers.
'Golddust' Mercardonia - This petite hybrid to 5-inches tall is a strong garden performer, covered with cheery yellow flowers May to October. Heat tolerant and low maintenance - no deadheading needed. Carpets baskets or border edges with color.

From Monrovia (www.monrovia.com)

'Bountiful Blue' Blueberry - All season garden interest and sweet blueberries make this semi-dwarf shrub an ideal addition to edible landscapes. Foliage is strongly blue-tinged, turning red in fall; white flowers are followed by large berries. Performs best near a different variety blueberry bush. Grows 3 to 4 feet tall and wide.
'Heatwave' Salvias - This Salvia greggii series popular in Australia for its heat and drought tolerance is ideal for water wise gardens here. Compact plants to 2 feet tall bear blooms in shades of lavender, pink, rose and white. Hummingbird favorites.

From Mountain States Wholesale Nursery (www.mswn.com)

Chrysactinia mexicana - Low growing mats to 2-feet tall and wide of aromatic foliage are a backdrop for daisy-like flowers in a traffic-stopping intense yellow. Shear lightly for repeat bloom. Water deeply once a week. Heat tolerant.
Yucca pallida - Nursery rep Wendy Proud calls this succulent the "new agapanthus" for its dramatic four foot tall flower stalks that bear pure white bell-shaped flowers for two months starting in spring. Blue-green leaves are edged in yellow-pink; sharp tips can be clipped off. "Not your grandmother's yucca," Proud adds.
After Bulbs Bloom
Many popular spring bulbs finish blooming this month. Some, like tulips and hyacinths, are annuals in our climate and can be yanked from the ground when the flowers fade. Others, like daffodils and baboon flowers (Babiana), will return next year. To keep them vigorous and encourage them to naturalize or multiply, cut off spent flower stalks but leave the foliage to continue to provide nutrients to replenish the bulbs. A light feeding helps this process. Remove leaves only after they turn yellow or brown. If they become unsightly, they can be tucked out of sight.
Aloes Light Up Winter

Aloes are a sure bet for winter color in San Diego gardens. These succulents, ranging from ground-huggers to fantastical trees, send up spikes of blazing red, orange or gold flowers January through April. Some favorites are:

  • Aloe barberae (formerly A. bainesii) – Sculptural “Dr. Seuss” 20-30-foot tree aloe with rosy, striped flowers in some years. Frost tender.
  • Aloe plicatilis – Fan aloe to 3 feet tall prized for tongue-depressor-shaped leaves atop gray sculptural branching and scarlet flower spikes.
  • Aloe cameronii – Star fish aloe with chocolate-burgundy serrated leaves that form 3-foot wide rosettes. Fiery orange-red flower spikes.
  • Aloe ‘Cynthia Giddy’ – Two-foot tall and wide rosettes with speckled leaves and tall coral-red flower spikes. Reblooms.
  • Aloe somaliensis - Reptilian-patterned green and silver leaves and small stature are perfect for containers. Glowing red tubular flowers.
  • Aloe ‘Donnie’ – One of several 2-4-inch tall hybrids from Proven Winners, ‘Donnie’ has spotted leaves edged in pink. Ideal for containers.
Alstroemeria Flower Power
tricolor

As companions to the season's poppies, snapdragons and other classic annuals, consider alstroemerias, a perennial with charming freckled blooms that add beauty to the landscape and vase year round. Garden Glories Nursery in Vista specializes in these and other choice plants. Here are some of owner Liz Youngflesh's favorites: Three-foot tall classics 'Casa Blanca' (pure white and rose), 'Third Harmonic' (soft orange that's a perfect foil to blue and purple flowers) and 'Kyty' (shades of butter yellow); two-foot tall mid-size 'Rosea' (sweet dusty rose), 'Ice' (frosty peach with pale green throat) and 'New Beginnings' (yellow blushed with soft pink); and hard-to-find 'Rachel' (rich purple) and 'Charly' (medium red). Give alstroemerias sun to part-shade, well-amended soil and regular water. Visits to Garden Glories are by appointment (www.gardengloriesnursery.com). Youngflesh, a Master Gardener, also sells at many of the San Diego Horticultural Society monthly meetings.

Australian Plants for San Diego Gardens

Plants from areas around the world with Mediterranean-style climates like ours fit easily into San Diego gardens. One rich source is Australia and one of Down Under's biggest fans is Mo Price, a Master Gardener who lectures on Australian plants. Below are some of her favorites, all tested in her Encinitas garden. Give these flowering beauties good drainage and once established, minimal water unless otherwise noted.

Dampiera diversifolia - This trailing groundcover, ideal for rockeries, slopes and containers, is covered with brilliant purple-blue flowers in spring and summer. Spreads up to 6 feet wide, but is not invasive or weedy. Tolerates moderate frost and some drought. Full sun, except inland where afternoon shade is desirable.

Thryptomene - These tough shrubs 2-3 feet tall and wide bloom non-stop with dainty pink or white starry flowers that can be cut for bouquets. Not fussy about soil if well drained; easily pruned to shape. Full sun to part-shade.

Dianella (Flax Lily) - Aborigines favor the fibrous strappy leaves of some species to weave baskets. Gardeners love them for their blue flowers with sunny yellow stamens that are followed by electric blue berries that last for months. Forms clumps 2 feet tall. Newer hybrids have variegated leaves. Moderate water.

Eremophila (Emu Bush) - The name of these 4 foot tall and wide shrubs means "desert loving" which suggest how important it is to provide full sun and only minimal water. Tubular pink or yellow flowers in summer are followed by fleshy fruits popular with birds and other animals. Thickish leaves vary from green to blue- and gray-green.

Grevillea lanigera (Woolly Grevillea) - Spidery pink and cream flowers cover this gray-green leaved shrub from January through October. Mounding to 4 feet tall and 6 feet wide. Many hybrids, including dwarfs, are available. Full sun.

These plants and many other Australian natives can be found at specialty nurseries throughout San Diego County.

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.

Check trees for pests
Inspect trees weekly (especially new growth) for signs of pests. Wash foliage periodically with a forceful spray of water to dislodge aphids, spider mites and whiteflies. If an insecticide is needed, use a chemical with short residual activity, such as insecticidal soap, horticultural oil, pyrethrin, or Bt (for caterpillars)to protect beneficial insects
Control powdery mildew on grapes
Control powdery mildew on grapes. Apply sulfur dust when new shoots are 6", 12", 18" and 24" long. Then every two weeks, or as needed until harvest.
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.
Don’t Irrigate in the Rain
Monitor irrigation and adjust it to suit the weather, which is very variable this month. Use the Be Waterwise calculator (http://www.bewaterwise.com/calculator.html) to find out how long your sprinklers should run. Shorter, cooler days reduce water stress on established plants, while bursts of heat, especially from Santa Anas, up the need for water. The changing season also can shift shadows to places that earlier basked in the sun, also reducing irrigation needs. Sprinklers may need to be adjusted too, to accommodate summer plant growth or the addition of companion perennials and annuals. Since months may have passed since your last check, inspect the system for leaks and water waste. With everyone watching water consumption, don’t irritate neighbors and drain your bank account by watering during a rainstorm. Hit “rain delay” on your timer whenever precipitation is forecast.
Feed Growing Succulents
As the seasons change, new growth should start to appear on many succulents that were dormant during winter. This is a good time to start fertilizing them using a balanced granule or liquid fertilizer (20-20-20). Dilute it to half strength. Be sure plants in containers or in the ground are watered before applying the fertilizer. If granule fertilizer is used, water it in after scattering it on the ground.
Feed New and Established Plants
Help plants thrive with an application of fertilizer rich with the nitrogen too often in short supply in San Diego soils. Nitrogen content is indicated by the first of the three numbers on a fertilizer bag; pick one with more nitrogen (N), than phosphorus (P) (the second number) or potassium (K) (the third number.)

Scatter fertilizer granules lightly and evenly at the edge of the plant's rootball or foliage-drip line, scratch it into the ground taking care not to harm feeder roots, and then water lightly if soil is not moist from recent rain or irrigation. It's tempting to fertilize when rain is forecast, but heavy showers could carry granules away in runoff.

A new layer of mulch will help build organic content in the soil, but at a slower pace. Mulch also will help hold moisture in the ground as temperatures start to climb. For container plants, a time-release fertilizer is a good choice to keep nutrition high in the limited amount of soil available to the plant.
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.
Fertilize citrus
Apply fertilizer high in nitrogen such as ammonium sulfate (21%N), for blood meal (13%N) Feb – June4-6 weeks apart. See Citrus for the Home Garden for the amount of fertilizer to use on young and mature trees. http://www.mastergardenerssandiego.org/downloads/citrus%20for%20home%20garden.pdf If you use a citrus fertilizer, follow label directions. (Avoid products that use Murate of Potash to supply potassium).
Fertilize fruit trees
Apply fertilizer high in nitrogen to mature fruit trees Most mature fruit trees (5 years and older) require the equivalent of one-pound of actual nitrogen annually. One pound of nitrogen can be supplied with 5 pounds of ammonium sulfate (21% N), or 8 pounds of blood meal (13% N) Divide the amount of fertilizer required for one year into three equal lots and apply them six weeks apart, starting in the spring after new growth begins.
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 www.ipm.ucdavis.edu.

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.

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.
Grow A Backyard Orchard

January is the perfect time to add apple and stone fruit trees to an edible landscape. Nurseries tend to have the largest selection during bare-root season when these deciduous trees are bargain priced. Many are supplied by Dave Wilson Nursery (www.davewilson.com), one of California’s largest growers of fruit trees.  Here are some suggestions from Tom Spellman, Dave Wilson Nursery Southwest sales manager. Plant now but don’t allow fruiting during the first year while the tree becomes established. Grow a moderate crop the second year; enjoy a full crop in the third.

Dorset Golden Apple – A very reliable producer, this apple requires minimal “chill hours” to set fruit, making it ideal for coastal as well as inland areas. Pick fruit as early as mid-June. Apples are bright yellow blushed with red and pink; flesh is crisp and firm
Stark Saturn Donut Peach – Disc-shaped fruit with a dimpled center on this gourmet white peach ripens in July. Flavor is “very peachy with hints of almond,” Spellman says. 
Red Baron Peach – This tree is beautiful – and bountiful. In bloom with double bright red flowers, Red Baron rivals many ornamental peach trees. Yellow freestone fruit is large and juicy.
Burgundy Plum – This tree bears juicy ruby-red fruit from mid-July to September. A Japanese-style plum, it is a good pollinator for other plums and pluots. Deep burgundy flesh is sweet, without tartness.
Flavor Delight Aprium – Apricot lovers generally can’t tell that this hybrid has been crossed with a plum. The breeding gives apriums greater adaptability than finicky apricots.  Fruit is gold blushed inside and out and ripens as early as mid-May.
Arctic Star Nectarine – Sweet, juicy, low-acid fruit can be enjoyed starting in June from this recent introduction. Deep red skin is a vivid contrast with the white flesh.
Bella Gold Peacotum – Peach, plum and apricot combine in this 2011 introduction. Golf ball-size fruit is amber with a red blush. Flavors reflect all three parents with an emphasis on plum and a hint of citrus. Attractive landscape tree with white flowers in spring. Needs a cross pollinator.
Flavor Grenade Pluot – Oblong yellow-green fruit tinged with red “explode with plumy apricot flavor,” Spellman says. Late bearing and suited to low-chill areas like San Diego. Showy white flowers in spring. Needs cross pollinator.
Dapple Dandy Pluot – Egg-shaped, cream fleshed fruit with marbled maroon and gold skin ripens in late July to early August. A consistent taste-test winner. Needs a cross pollinator.
Flavor King Pluot - Garnet skin and fruit with a spicy scent and flavor make this a taste test winner and a favorite of backyard orchardists, who also appreciate its handsome form. Bears in late July into August. Needs a cross pollinator and good choice as a cross pollinator for other pluots.
Spice Zee Nectaplum - This self-fertile combo of plum and nectarine bears large red fruit with mottled flesh with predominate nectarine flavor. Double pink flowers in spring and dark greenish-red leaves make it one of the most highly ornamental fruit trees. Long bearing season from June to August.
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 (www.arrowheaddahlias.com) for tubers and Corralitos Gardens (www.cgdahlias.com) on California's Central coast for rooted cuttings.

Grow Hydrangeas

Hydrangeas are showy flowers that brighten any winter garden. While they have a reputation as water guzzlers, their water needs can be reduced with proper siting out of direct sun and lots of mulch to hold moisture in. Small additions of aluminum sulfate in the weeks prior to spring bloom can transform some pink-flowered varieties into blue beauties. Here are some favorites.

‘Ayesha’ – A soft floral scent rises from the mauve-pink flowers on this Hydrangea macrophylla hybrid. Change them to cornflower blue with aluminum sulfate. Serrated leaves are deep green. Grows 3 to 4 feet tall and wide. Prolific bloomer.
‘Nigra’ – Black stems accent the dark green leaves and saucer-sized rosy pink mophead flowers. Aluminum sulfate turns them blue flushed with purple. Reaches 3 to 4 feet tall and wide. Blooms from spring through August.
‘Preziosa’ – Stems are purple and leaves have a purple haze on this dramatic mophead with creamy flowers that turn rose as they age and violet-pink when dry. Grows 2 ½ feet tall and wide. Dense habit.
‘Limelight’ – This H. paniculata hybrid from Holland is a vigorous grower to 5 feet tall. Lacy conical booms are a refreshing lime green with a blush of pink as they age. Open habit.
‘Forever Red’ – Dinner plate-size blooms are the reddest found on a hydrangea.  Mophead flowers have a purple cast as they age. Stems are burgundy-red. Shrub reaches 4 feet tall and wide.
‘Mariesii Variegata’ - Green foliage splashed with cream and light pink lacecap flowers brighten shade gardens. Flowers turn blue with addition of aluminum sulfate. Can take full sun on the coast. Grows to 3 feet tall and wide.
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 www.mastergardenerssandiego.org and click on Resources. Another good guide is "Sunset Western Garden Book of Edibles."

Grow the Scent of Spring
Along with the heady smell of citrus blossoms, the perfume of jasmine signals the arrival of spring here. Plus its tiny star-shaped white blossoms elegantly dress any structure this strong evergreen vine embraces. A native of China, Jasminum polyanthum is sometimes known as pink jasmine for its rose-hued flower buds or winter jasmine for the start of its bloom cycle. Handsome foliage is dark green with a lighter green underside. A vigorous grower, this vine can reach 20 feet, easily covering a fence or trellis. The sweet scent, a staple in perfumes for centuries, lures pollinating moths but works its magic on humans too, so plant it where you can enjoy it. The vine can be cut back hard after bloom to clean up the plant and promote growth for next year's spring flowers. Jasminum polyanthum is available in most area nurseries.
Harvest Rain

With average annual rainfall here of less than 11 inches, it pays to make the most of every drop. Start by redirecting water from gutters routed into storm drains to empty into the garden instead. A simple swale – a depression lined with gravel – also can collect runoff so it can percolate into the ground. Rain barrels too offer simple storage; most fill up remarkably fast, so install more than one if possible.

The Water Conservation Garden on the campus of Cuyamaca College in El Cajon has a good exhibit of a working rain barrel system. Details are at www.thegarden.org.

How to Harvest Some Winter Veggies
Many winter vegetables started in October or November are ready for harvest now. To enjoy their sweet tender leaves, cut cabbages when they are rock-hard; if they feel springy, they need more time. When broccoli buds are full and firm, cut the stalk with a knife. Leave both cabbage and broccoli in the ground and they’ll continue to produce, especially with the benefit of a side-dressing of vegetable fertilizer. Cauliflower, though, forms only one head. To keep it snowy white, pull the leaves up over the head and tie them to block out the sun. Harvest when the buds are full and close together. When they begin to separate, you’ve waited too long. If you haven’t grown lettuce, now is still a good time to plant seeds or transplants. The cool weather will give you a crop quickly, and “the cut and come again” harvest keeps you in fresh salad greens for weeks.
Irrigate fruit trees & vines
Irrigate established fruit tress and vines when soil 3-4 inches deep begins to dry out. Apply enough water to wet soil 2-3 feet deep.
Keep ants off trees
Keep ants off trees by wrapping a band of heavy paper or duct tape around the trunk and coating it with a sticky material like Tanglefoot. Trim branches that touch other objects or the ground to stop ants from going around the barrier. Also place ant stakes (small containers with toxic bait) by ant nests and trails.
Learn more about pest management
Visit www.ipm.ucdavis.edu to learn more about safe pest management. UC Pest notes provide information on common garden pest and disease problems.
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.

Order seed
Buy seed of warm season vegetables for planting in the Spring and Summer.
Paint tree trunks with whitewash
Paint the trunks of fruit trees (especially newly-planted and young trees) with whitewash to protect the bark from sunburn injury. Use equal parts water and white interior non-enamel flat latex paint. Whitewash trunks from 1 inch below ground level to at least 2 feet above to prevent sunburn.
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 cool-season vegetables
Plant cool-season vegetables that will mature before hot summer weather arrives. Plant beets, carrots, celeriac, chard, chives, endive, leeks, green onions, parsley, parsnips, endive, lettuce, peas, potatoes (white), radishes, rutabaga and spinach.
Plant for Summer

While weather is warming, temperatures are still temperate enough to plant. This month it's easy to be tempted by seasonal color brightening nurseries, but experienced gardeners set their sights on summer and purchase plants accordingly. Avoid planting spring blooming annuals like ranunculus, stocks, snapdragons, pansies and poppies now; they will soon fade. Instead choose six-packs and four-inch pots of summer flowering plants that, if planted now, will be ready for the hot, dry conditions ahead. Some to consider are petunias, zinnias, rudbeckia, coreopsis, asters, annual salvias, cosmos, yarrow, gazania, marigolds, sunflowers and nicotiana.

Plant Perennial Performers

There's still time to add perennials to the garden while moderate air and soil temperatures encourage, rather than stress plants. Pick some tried and true performers with long-lasting floral displays and few demands. Among them, to name a few, are alstroemeria, verbena, coreopsis, Asclepias tuberosa (sunny flowers and Monarch butterflies - it's their host plant), and agastache. With the rainy season behind us, take care to water these new additions regularly and deeply during their first season in the garden.

Plant warm season vegetables
Plant warm season vegetables when and soil are warm. Plant beans (snap), cantaloupe and other melons, sweet corn, cucumber, eggplant, Florence Fennel, peppers, sweet potato, squash (summer and winter), and tomatoes and watermelon.
Prepare Edibles Beds
Before planting warm season vegetables, remove spent winter growers from beds and turn the soil, incorporating compost and a complete fertilizer high in phosphorus. Apply chemical fertilizers just before planting. If manures are used, apply them several weeks before planting and irrigate to leach salts from the surface soil. Apply no more than 20 pounds of poultry manure or 50 pounds of steer manure per 100 square feet.
Prepare soil for planting
Prepare soil for planting by incorporating compost and a complete fertilizer high in phosphorus. Apply chemical fertilizers just before planting. If manures are used, apply them two weeks before planting and irrigate to leach salts from the surface soil. Apply no more than 20 lbs. of poultry manure or 50 lbs. of steer manure per 100 square feet.
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 www.reneesgarden.com. 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.

Prune Camellias

Camellia Nuccio

Prune camellias before new growth starts or while new growth is under an inch long. Cut the branch back to its origin or to an outward pointing growth bud or dormant bud eye and don't leave more than a 1/4-inch stub at the cut. Keep in mind the three universal pruning points:

  1. Remove all dead or weak branches
  2. remove all crossing branches
  3. remove branches to open up the center of the plant in order to allow light to enter and air to circulate.
While cleaning up after pruning, be sure to remove fallen blooms that can harbor a fungus that causes petal blight.

Prune Frost Damage
When the freeze threat dwindles and trees and shrubs begin to bud, is the time to prune unsightly frost damage. Though it's tempting to trim limbs right after a killing chill, waiting is worthwhile. Damage may be only superficial and, come spring, affected branches may leaf out again in full or in part. If that doesn't happen, prune back any damage with an eye toward maintaining an attractive shape. Use sharp loppers to make clean cuts. Follow with water and fertilizer to spur new growth. And once frosty nights are history, don't forget to move plants you've sheltered back to spots where they can enjoy the warm spring sunshine.
Rose Slug Remedies
carrot

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 apples after bloom to control codling moth
Spray apples after bloom to control codling moth (wormy fruit). Apply carbaryl (Sevin) after petals have fallen and again three weeks later.

For other control methods see the UC Pest Note on Codling Moth at www.ipm.ucdavis.edu.
Thin fruit on fruit trees
Begin thinning fruit of apples, pears, and stone fruit peach, nectarine, plum and apricot when they are about 1/2" in size. Space fruit four to six inches apart. Leave one fruit per spur. Thin early-maturing varieties earlier and heavier than late-maturing varieties.
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, www.mastergardenerssandiego.org. 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.

Try Top Tomatoes

A sweet juicy tomato from the garden - ah, heaven! These days, homegrown tomatoes come in exotic shades of pink, purple, yellow and more and range from bite size to hefty four pounders.

Scott Daigre grows more than 300 varieties of tomatoes for his Tomatomania sales, including the one at the San Diego Botanic Garden March 20 and 21. He also sells online at tomatomania.com. Here are some of his favorites:
Green Zebra - Chefs discovered this green striped tomato and helped make it an edible garden classic. "It pushes the taste barrier," Daigre say. "It's spicy, tangy, different." Beautiful on a salad plate.
Jaune Flamee - Another saladette tomato, Jaune Flamee (yellow flame) turns tangerine colored and often shows a pink blush when ripe. "It loves the heat and will produce forever," Daigre says. Taste is sweeter and milder than the typical "big red tomato taste."
Cherokee Purple - This American heirloom is considered one of the black-purple tomatoes but Daigre describes its color as closer to mauve. A slicing tomato, Cherokee Purple has "the most outrageous tomato taste ever." Plant is a consistent producer over a long season.
Sungold - Daigre calls this the world's favorite tomato... and no wonder. Its golden cherries are sweet and juicy, perfect for snacking and convincing kids to eat their veggies. An early, prolific producer.
Aussie - This pink-hued heirloom, Daigre says, is "everything a beefsteak should be." It bears later in the season when other tomatoes may slow down. Great in a sandwich.
Ramapo - If you crave the much-touted Jersey tomatoes, Ramapo is for you. It was developed by Rutgers University four decades ago and credited with starting the Jersey tomato craze. Off the market for 20 years, it's been reintroduced this year. Medium-sized tomato with great taste.
Yellow Pear - Another chef favorite, this lemon yellow, petite, pear-shaped beauty dresses up any salad. As reliable along the coast as inland. "It's kind of irresistible," Daigre says.
Marvel Stripe - This bicolor heirloom is yellow streaked with red. It really shows its beauty, though, when sliced; no two look alike inside. "It's like a pinto pony," Daigre says. "Plus it's lusciously sweet, succulent and wonderful."
Wildflowers on Parade

After winter rains - assuming Mother Nature has been generous - California deserts, valleys and mountains burst into bloom. Luckily for urban dwellers, there is a hotline that helps you time visits to big bloom sites nearby. From mid-March until May, the Theodore Payne Foundation wildflower hotline offers weekly updates on what is blooming where, starting with desert wildflowers and ending when wildflowers carpet mountain meadows. Verbal updates are augmented by longer written reports on the foundation's Web site. The hotline number is 818-768-3533; Web site is www.theodorepayne.org.

Win the Battle Against Slugs and Snails

Cloudy damp winter brings out slugs and snails. If these pests are nibbling on seedlings and other tender plants, here are some ways to fight back that won’t harm the environment.


Start by eliminating daytime hiding places under rocks, pieces of wood or dense foliage. Handpick any snails found, put them in a bag and dispose in the trash. Potted plants and trees can be protected with a band of copper flashing that the snails and slugs won’t cross. Recently introduced baits made from iron phosphate and marketed as Sluggo or Escar-Go are safe to use around wildlife, pets and children. Another option is to introduce decollate or so-called “killer” snails into the garden. Search on line for a local distributor.


More info on snail and slug control is at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7427.html

Win the Pest Battle
Spring also gives a boost to garden pests. Here are a few simple controls that won't harm bees, beneficial insects or the environment.

For aphids, soft-bodied insects that cling to rose and citrus foliage, blast them with water to knock them off or (if you're not squeamish) squish them with your fingers.

For geranium bud worms and ugly tomato horn worms, spray with all-organic Bt (Bacillus thuringiensis), bacteria that target only caterpillars without harming beneficial insects, people or pets.

For a mild infestation of fuzzy white mealy bugs, dab the pests with rubbing alcohol.

To combat common brown snails, release decollate snails that feast on them, not plants. Good sources can be found on line.