What to do in your Southern California garden in August
Move over, orange! This year, plant carrots in hues of purple, cream, and yellow. In Sunset’s Test Garden, we grew ‘Yellowstone’, ‘Purple Haze’, and ‘White Satin’ and loved the color and taste of all three. Prep a sunny bed by removing stones and clods 1 foot deep to ensure smooth, straight carrots; sow seeds directly, and keep soil evenly moist. When seedlings are a few inches tall, thin to 1½ inches apart. The above varieties reach maturity in 65 to 75 days; check for size before then by pulling a few, and enjoy them as finger-size baby carrots.
Tired of freesias? Plant Ipheion uniflorum, an Argentine charmer with six-petaled blue or white flowers, or species tulips such as Tulipa bakeri and T. clusiana, which require no chill and will naturalize. In areas that stay dry in summer, try California natives including Calochortus, Dichelostemma, and Triteleia. Good sources are Brent and Becky's Bulbs (877/661-2852) and Telos Rare Bulbs.
Grow bearded irises Despite their ethereal flowers, these plants are very tough and drought tolerant, and late summer is the ideal time to plant rhizomes. For maximum impact, choose varieties such as 'Feedback', 'Frequent Flyer', or 'Summer Olympics', which provide several bloom cycles per year.
Sow broccoli and its kin. Coastal (Sunset climate zones 22-–24), inland (zones 18–21), and high desert (zone 11) gardeners can start germinating broccoli, brussels sprouts, cabbage, cauliflower, collard, kale, mustard greens, and other Brassica seeds in flats. Place flats in partial shade, and keep soil consistently moist until seeds sprout. Transplant seedlings into the garden when they’re about 4 inches tall.
Try a cool-colored bloomer. If just looking at your parched garden makes you feel hot, add Angelonia to your containers or borders. This South American perennial thrives in heat, and the mere sight of its blue, purple, or white blossoms will cool you off. They are good cut flowers too.
Dig up old, overgrown clumps of bearded irises and divide rhizomes with a sharp knife. Discard woody centers. Trim leaves of remaining rhizomes to 6 inches. Replant divisions 1 to 2 feet apart.
Keeping plants irrigated is a gardener's most important task this month. Vulnerable container plants may need a daily soaking. Shallow-rooted plants like avocado and citrus need to be watered more frequently as well. Established shrubs, perennials, and shade trees will benefit from a slow, deep soak. In addition, mist plants with a hose occasionally to keep foliage clean and wash away pests like spider mites.
Cut back spent hydrangeas, but not too hard; leave at least three buds per stem for next year's blooms. Cut back rangy annuals and perennials by at least one-third. Cut back fuchsias and marguerites to encourage new blooms. Pinch back impatiens and pelargoniums. Trim ornamental hedges lightly. Prune off water sprouts from citrus and stone-fruit trees. Pull suckers off wisteria vines.
Birds, like other creatures, need lots to drink during hot weather. They find moving water like that from misters, drippers, and water features especially attractive.
Dry vegetation and Santa Ana winds are a bad combo. If you live in a fire-prone area, remove all dead limbs and leaves from trees and shrubs, especially those near the home, and cut tall grasses and weeds down to stubble. Clean leaves from gutters, and remove woody vegetation growing against structures. If you don't have an evacuation plan, develop one; if you do, have all family members review it.
If your daylilies suffer from rust, try cutting the foliage back to the ground after the bloom cycle. Rust usually occurs on older leaves. New foliage will stay rust-free for several months.
Scale, spider mites, and thrips may attack houseplants during summer months. Mist plants frequently to increase humidity and reduce stress. Treat plant infestations with insecticidal soap, following label instructions.
Irregular brown patches in summer lawns may be caused by beetle larvae, which feed on grass roots. Pull up sections of the dead turf. If you find grubs, treat your lawn with beneficial parasitic nematodes. Following label instructions, spray the nematode-water mixture over the turf in late afternoon after the lawn has been watered. Gardens Alive (513/354-1482) sells Grub-Away, if you can’t find the nematodes locally.