Euphorbias. They add evergreen foliage color to borders, containers, and rock gardens. Euphorbia amygdaloides has dark green leaves. E. characias has blue-green leaves. Resembling a poinsettia (its cousin), E. heterophylla displays red- and white-blotched leaves in summer.
Palms. You can't beat palms for easy-care tropical ambience. At poolside, try Mediterranean fan palm ( Chamaerops humilis), Mexican blue palm ( Brahea armata), or queen palm ( Syagrus romazoffianum). Near desert natives, consider Hispaniola or Sonoran palmetto ( Sabal blackburniana and S. uresana), pindo palm ( Butia capitata), or windmill palm ( Trachycarpus fortunei). For the patio, consider a potted Costa Rican parlor palm ( Chamaedorea costaricana).
Seasonal color. Sunset climate zones 2b, 3a: Try 'Orange Zinger' or 'Red Splash' calendula, 'Lemon Gem' and 'Tangerine Gem' marigold, and 'Persian Carpet' zinnia. Zones 10, 11 (Albuquerque, Las Vegas): Consider 'Scarlet Fire' celosia, 'Blue Bell' or 'Blue Spire' larkspur, Double Pinwheel Mix marigold, 'Ace of Spades' scabiosa, and 'Canary Yellow' zinnia. Zones 12, 13: Try 'Picotee' or 'Yellow Garden' cosmos, 'Cempoalxochitl' marigold, 'Victoria' sage, 'Hopi Black Dye' or 'Tarahumara' sunflower, or 'Purple Dahlia' or 'Shades of Pink' zinnia. Seeds of these plants are available from Seeds of Change (888/762-7333).
Summer-blooming shrubs. Add a splash of bold orange or red blossoms by planting Baja fairy duster ( Calliandra californica), cape honeysuckle ( Tecoma capensis), firecracker bush ( Hamelia patens), orange bells ( Tecoma x alata), or red bird of paradise ( Caesalpinia pulcherrima). For bright yellow blooms, consider Mexican bird of paradise ( Caesalpinia mexicana), San Marcos hibiscus ( Gossypium harknessii), shrubby senna ( Senna wislizenii), and yellow bird of paradise ( Caesalpinia gilliesii). If you prefer pinks and purples, try Chihuahuan or Langman's sage ( Leucophyllum laevigatum and L. langmaniae) or Texas mountain laurel ( Sophora secundiflora).
Vegetables. Zones 2b, 3a: Sow seeds of broccoli, brussels sprouts, cabbages, carrots, chard, radishes, and turnips. Zones 10-13: Sow seeds of Armenian cucumbers, black-eyed peas, cantaloupe, chiles, corn, eggplant, early-maturing green beans, okra, summer and winter squash, and watermelon.
Care for roses. Zones 2b, 3a, 10: Cut off faded flowers, water two to three times a week, and fertilize every two weeks during bloom. Zones 11-13: Remove faded blossoms, discontinue feeding, and water deeply once a week.
Protect crops. To prevent birds and insects from damaging fruits and vegetables, drape trees and plants with bird netting or shadecloth. To prevent sunscald, cover vegetables with 50-percent shadecloth; this also reduces temperatures, which improves the ability of peppers and tomatoes to set blossoms and fruit.
Water wisely. Watch plants for heat stress, often signaled by brown spots, sudden leaf drop, or wilting that persists after sunset. If these symptoms occur, increase watering frequency. However, avoid overwatering, which can lead to yellowing leaves, blossom drop, and root rot. Irrigate when the top 2 to 3 inches of soil are dry. Potted plants may need water twice a day.