Calendulas are cheery, daisylike annuals that are easy to grow from seed. They bloom from spring until July or August in hot-summer areas and all summer in cooler locales. Edible petals add color to salads and soups. Sow seeds now for June flowers or purchase seedlings for instant color. Plant in a sunny spot and give moderate water. Choose old-fashioned forms, from orange-yellow 'Classic', pumpkin 'Orange Zinger', Pacific Beauty (a pale yellow to orange mix), and 'Pink Surprise' (mixed colors), to double flowers like 'Apricots and Oranges', crested double flowers like Kablouna Mix (apricot, gold, lemon, and orange), or quilled flowers such as orange 'Porcupine'. Seeds are available from Thompson & Morgan (800/274-7333) or Seeds of Change (888/762-7333).
You can start planting cool-season annuals in containers now. Choose a pot that withstands frost (copper, plastic, stoneware, terra-cotta labeled "frost-proof," or wood) and fill it with high-quality potting mix. Look for pansies, primroses, snapdragons, stock, sweet William, and violas. Mix in foliage plants such as chives, dusty miller, parsley, or vinca, or use vegetables with attractive leaves (sow seeds directly in the soil), including 'Bull's Blood' beets, ferny-leafed lettuce, Russian kale, or Swiss chard. Cover containers with a fabric frost blanket for a few days while plants acclimate and, after that, at night whenever cold weather threatens.
Amend sandy soil. Sandy and gravelly soils hold little water or nutrients, so drought stress and stunted growth may result. If you're uncertain which type of soil you have, take a sample to your local cooperative extension office. Before planting vegetables or ornamentals that require regular irrigation in sandy or gravelly soil, mix 4 inches of compost, 4 inches of manure, and 4 inches of peat moss into the top 12 inches of soil. Or choose sand-loving plants such as butterfly weed, catmint, common thrift, Cupid's dart, dianthus, gaillardia, lavender, santolina, sea holly, or sea lavender.
Divide perennials. Every few years, divide multistemmed perennials just after new leaves appear in spring to relieve crowding, create more plants, or improve the soil.
Apply mulch after your spring cleanup. The best mulch for dryland plants is screened gravel, river rock, or stone chips spread 2 to 4 inches deep. Austrian Black or ponderosa pine needles also work well; they are slow to decompose and don’t hold moisture against plants.
Related to wasps, yellow jackets can be a serious nuisance in late summer when they aggressively defend their territory (your garden). To attract the queens as they emerge from winter hibernation and before they build new nests, place traps out now. Hang them in out-of-the-way places to lessen the likelihood of being stung.
To control insect pests in your vegetable garden, lure in their natural enemies ― ladybugs, lacewings, hoverflies, and parasitic wasps ― by planting the nectar plants they love. These include aster, chamomile, coreopsis, cosmos, feverfew, marigold, scabiosa, and yarrow.
Frogs, lizards, toads, salamanders, and snakes eat huge numbers of pests, so draw them into your garden by providing shelter such as dry-stacked rock walls, mounds of moist organic mulch, or a pile of cut branches in an out-of-the-way corner. Also set shallow dishes on the ground, and keep them filled with fresh water. Avoid harmful pesticides and chemicals.