• Herbs. For fresh flavorings this summer, start an herb garden now. Plant chives, parsley, rosemary, sage, savory, sorrel, tarragon, and thyme. Sow seeds of arugula, chervil, and dill.
• Perennials. Early spring, when the soil is still cool and nurseries are full of choices, is a great time to buy and plant perennials. Euphorbia 'Diamond Frost', new from Proven Winners, is worth searching for. It looks like a short baby's breath and never stops blooming. Combine it with white-flowered Salvia x sylvestris 'Snow Queen' (another great performer) for a cool-looking, long-lasting, trouble-free display. One source for both plants is Cottage Nursery Gardens (714/890-5511) in Westminster.
• Summer bulbs. Continue to plant agapanthus, tuberous begonias, caladium, calla, canna, dahlia, gladiolus, lilies, tigridia, and watsonia.
• Tomatoes. There's still time to start tomatoes from seed (wait until April to plant them in the ground, as they need heat to thrive). Search catalogs such as Tomato Growers Supply Company (888/478-7333) for unusual varieties such as 'Prairie Fire', 'Sun Sugar', and 'Yellow Canary' ― worth trying for their names alone.
• Vegetables. Sow seeds for all-season crops such as beets, carrots, radishes, Swiss chard, and turnips. Or switch to summer crops and sow seeds of corn or green beans. Coastal gardeners can also plant cucumbers and squash. Wait until April to plant melons, as they need more heat; seedlings of unusual varieties, including 'Charentais', are available by mail from the Natural Gardening Company (707/766-9303).
• Fertilize. Almost everything in your garden needs a boost of nitrogen now. Feed fruit and ornamental trees, groundcovers, shrubs, perennials, and annuals that have been in the ground at least six weeks. Also feed turfgrass and container plants. Feed camellias after bloom, using cottonseed meal or an acidic commercial fertilizer.
• Prune ornamentals. Before their spring growth surge, prune boxwood, pittosporum, and other evergreen hedges. Prune spring-flowering trees such as cherry and plum after they bloom. Wait to prune frost damage from bougainvillea, Natal plum, or other subtropicals until you see new growth.
• Thin fruit trees. Begin thinning apples, pears, and other stone fruits when they reach about ½ inch in size. Remaining fruits should be about 4 to 6 inches apart.
PEST AND WEED CONTROL
• Control aphids. Strip them from plants by hand, wearing thin, disposable rubber gloves if you're squeamish. Or dislodge them with a strong blast of water from a hose.
• Deter weeds. To prevent annual weed seeds from germinating, apply a selective preemergence herbicide such as Green Light Amaze to your lawn. Follow label directions.
• Manage snails. Trap snails by allowing them to collect on lettuce leaves or under grapefruit rinds, or set out commercial bait.