Things to do in August
Banish Ants

In hot weather, ants head for potted plants, pet food and kitchen counters in search of food and water. To keep them away, be meticulous about cleanliness, plug tiny entry points and wash walls and counters where ants have marched with soapy water. To eliminate colonies, use bait stations with insecticides that foraging ants carry back to the nest. Over time these small doses will eliminate the colony. For free information on ants and other summer insect pests, visit

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.

Begin harvesting fruit
Begin harvesting fruit as soon as it is ripe.
Buy Bearded Iris
Starting mid-month, bearded iris rhizomes arrive in area nurseries. These drought-tolerant, spring show-stoppers now often bloom longer or more often, adding to their appeal to San Diego gardeners. Look for such rebloomers as pure white ‘Frequent Flyer’, burgundy and pale yellow ‘Paprika Fono’s’ and lavender and deep purple ‘Cloud Ballet’. When buying iris, look for firm, plump rhizomes with a fan of green leaves. Plant them with the top of the rhizome exposed to the sun.
Care for Reblooming Iris
Because they are fast growing and don’t go dormant after blooming like traditional bearded iris, reblooming bearded iris need regular water and feeding several times throughout the year to keep flowers coming. Low nitrogen fertilizers are best, especially in the heat of summer. Give plants a little now and water in. Rebloomers also appreciate a once-a-week deep watering, supplemented by shallow watering if temperatures soar. Watering in the cool of early evening can help reduce the potential of rhizome rot
Care for Roses

Rosarians recommend pruning roses at the end of the month. Cutting back by one-third will invigorate the plants for a fall bloom that rivals that of spring. Renew mulch and deep water once a week to encourage new growth. Probe the soil to be sure water penetrates the root zone and to prevent over watering. Mist leaves on the hottest days to reduce heat stress.

Check for zinc & iron deficiency
Inspect new leaves for signs of zinc and iron deficiency (yellowing between veins). Apply micronutrient spray if needed.
Continue Summer Veggie Care
Edibles benefit from regular irrigation and a feeding during summer when they are setting and maturing their tasty fruits and vegetables. Young warm-season vegetable plants may need water twice a day during a heat wave; plants that are flowering or starting to form a crop generally need more water than older plants. Check after watering to be sure water is reaching well down into the root zone. Since water retention varies in different soils, learn how quickly your vegetable bed dries out and needs additional water. A “side-dressing” of a balanced fertilizer mid-season also aids these productive plants. Spread the granules in a line 3-4 inches from the plant stem, scratch lightly into the dirt and water in. Avoid over-feeding that stimulates foliage growth at the expense of fruit production.
Control Corn Earworm
Control corn earworm, apply carbaryl (Sevin) or BT when silk first emerges, then every three days (Sevin) or 1-2 days (BT) until silk turns brown.
Cover seeds for protection
Cover seed with floating row cover to protect young plants from insects.
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.
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.
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 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 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."

Harvest Homegrown Crops

To enjoy the full flavor of vegetables grown in your garden, don’t allow them to linger too long on the vine. In just a few days, zucchini go from tender and tasty to tough and bland. Harvest daily to savor cukes, beans and squash while they are still young. Pick corn when the silk turns brown and juice in the kernels is milky and sweet. Ripe melons literally fall off the vine. Eggplant should be shiny and purple-black. Pinch flowers off basil and other herbs to keep them at their culinary best. Visit the UC Davis’ Vegetable Research Information Center ( ) , for details on planting and harvesting more than two dozen edibles.

Help Succulents Survive Summer
Be aware that most succulents need help coping with summer heat and aridity. Master Gardeners Laura and Don Starr who create succulent planters and garden designs for The Grateful Shed, recommend watching for shriveled, still green leaves – a warning that the plants are stressed and need water immediately. Many succulents are summer growers and benefit from weekly summer water – more often if planted in containers or rock gardens or during a heat wave. Water in the cool of morning and avoid getting water on the rosettes of echeverias and other flat or broad-leafed varieties. Also during these hot months, move succulents in containers into an area with some midday and afternoon shade.
Join a Garden Group

New and experienced gardeners here benefit from classes and clubs in tune with the rhythms of Southern California horticulture. This is a good month to join a community garden club or plant organization that have monthly meetings and/or newsletters chock full of locally-based garden tips. County-wide groups include the San Diego Horticultural Society ( ), San Diego Floral Association ( ), and San Diego Edible Garden Society ( ).

Keeps ants off trees
Keep ants off trees and periodically wash foliage with a forceful spray of water to promote biological control of spider mites, aphids, whiteflies, scale and other insects.
Last planting of warm season vegetables
Make a last planting of warm-season vegetables (tomatoes, peppers, eggplant, corn, beans, summer squash) in July for fall harvest.
Minimize Bolting

In warm weather, basils often “bolt” or go to seed prematurely. To keep these annuals producing lots of flavorful leaves, pinch off flower stalks before they have a chance to grow and bloom. If allowed to flower, leaf production stops as the plant sets seed and ultimately dies. Cilantro is another herb notorious for bolting since it has little tolerance of hot weather and soil temperatures above 75 degrees. One solution is a sunny planting site with partial shade in the afternoon and a layer of mulch for the root zone. Another option is to plant slow-bolting varieties like ‘Caribe’ and ‘Calypso’ from Johnny’s Select Seeds (  

Monitor moisture
Monitor soil moisture within the root zone and irrigate when soil in the top 4 inches begins to dry. Periodically apply enough water to leach salts below plant roots (three to four feet deep).
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.
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 cole crops
Plant seed of cole crops (cabbage, broccoli, cauliflower) in August for winter harvest.
Plant for Fresh Summer Color
Early in the month is a last opportunity to add annuals that will refresh summer-seared gardens with color into fall. Opt for tried and true zinnias in some new colors, tall ‘Goldsturm’ rudbeckia with its yellow petals and black eye or cosmos now available with frilly double blooms. Or experiment with something new like the South African annual Ursinia ‘Solar Fire’ with its golden yellow petals and hot-red centers or sunflowers in mahogany hues. When planting from six-packs or four-inch pots, be sure to water regularly until established. Provide additional moisture if a heat wave strikes.
Prune blackberry & raspberry canes
Prune out blackberry and raspberry canes that have borne fruit.
Prune out damaged shoots
Prune out shoots killed by fire blight on pear, apple, quince and loquat. Make cuts at least 12 inches below (if possible) infected tissue and disinfect pruning shears between cuts.
Remove damaged fruit
Remove fruit that is damaged or on the ground to discourage green fruit beetles and other insect scavengers.
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.

Start a Garden Diary
August is a good time to reflect on your landscape’s design and performance with an eye on the fall-planting season ahead. As you relax in the garden, take notes on its pluses and minuses, sketch in changes and record plants that have caught your eye on a garden tour or in a nursery. Garden journals also are good place to store plant tags, empty seed packets and the like. so they aren’t lost. A garden diary can be a simple notebook or a ring-bound, multi-year “Gardener’s Journal” available in area book stores or from online retailers.
Summer Container Care
Container plants need constant monitoring in summer. Soils dry out quickly, which makes regular watering a must. Water deeply so damaging salts from San Diego-area water are flushed out the pot’s drainage hole. Constant watering depletes nutrients, making summer feeding with a slow-release fertilizer a must.
Summer Water and Native Plants

Water is often the culprit when California native plants die young. Adapted to wet winters and dry summers, these plants succumb to fungal diseases and rots when watered too much in hot weather. Yet newly planted and established natives benefit from some supplemental moisture in summer. Short duration and/or overhead watering – often typical garden irrigation - are the worst. Instead opt for longer drinks from drip systems or soaker hoses. (Move drip emitters away from the base of plants when they are established to avoid crown rot). Established plants often get by on monthly soaks, while newly planted natives may need weekly or twice monthly watering during their first two years in the garden. Water recommendations for specific plants are on the web site of Tree of Life Nursery, native plant growers, at

Support limbs
Support limbs that have a heavy fruit load to prevent breakage.
Watch for Diaprepes root weevil damage
Watch for Diaprepes root weevil damage on citrus and other woody plants. Report infestations to the Exotic Pest Hotline (1-800-491-1899). To see photos of the pest and damage visit: and enter “Diaprepes” in the search box.
Withhold water from rhubarb & artichoke
Withhold water from rhubarb and artichoke and allow plants to go dormant until fall.