April in the garden

April may be known for showers, but you don't have to wait until May for great flowers. In addition to spring-flowering bulbs, many gardeners use cool-season annuals for adding color to early-season landscapes.

The list of annuals that can be planted outdoors early this month includes the classics: pansies, primroses and snapdragons. But it also includes pouch flowers (Nemesia), bush violets (Browallia), cape daisy (Osteospermum), painted tongues (Salpiglossis) and a rainbow of others.

Most cool-season annuals falter as temperatures rise. If you prune them hard and move them into cool shade, many will spring back to life in fall.

Here's what you need to do in the garden this month:

General garden care

h Continue to remove all garden debris from last year. Shred and compost, leaving out all diseased material.

h Plant perennials, hardy ornamental grasses and roses. When planting bare-root plants, soak the roots in a bucket of water for several hours before planting.

h Plant trees and shrubs. Mulch newly installed woody plants and irrigate during weeks with less than 1 inch of rainfall.

h If a layer of organic mulch was not placed last fall, add 2 to 3 inches to garden beds this month. Avoid placing mulch over crowns of plants. Pull mulch away from trunks of trees and shrubs.

h Crab grass control can be spread on lawns in early to mid-April before weeds germinate.

h Early in the growing season, renew efforts to discourage wildlife from forming browsing habits. Physical barriers are the most effective approach to preventing damage. One approach is placing three rows of black string no more that 18 to 24 inches apart around plants that are known favorites. Use spray repellents as necessary.

Flowers

h Later in the month, plant Shirley, Iceland and California poppies and Persian buttercups.

h If botrytis blight or bud blast was a problem last year, spray newly emerging peonies with an approved fungicide when plants are 2 to 4 inches tall. Avoid overhead watering. If fungus persists, consider relocating peonies to a more open, full-sun site in the fall.

h When peonies reach 10 inches, stake or hoop them to support their blossoms.

h Divide mature summer- and fall-blooming perennials when they are 4 to 6 inches tall. Do not divide Oriental poppies or iris this month.

h Remove spent flowers of spring-flowering bulbs, but allow leaves to wither completely before they're removed. If properly planted bulbs are showing signs of decline (fewer, less showy blossoms), use a slow-release fertilizer in early fall.

h Begin uncovering roses. Remove mulch and carefully hose away mounded soil. Avoid using sharp tools around bases of rosebushes. Apply a 6-2-0, organic, slow-release fertilizer such as Milorganite.

Trees and shrubs

h If apple scab was a problem last year on crab apple trees, remove any remaining old leaves and fruits from branches and soil beneath trees. Prepare to start spraying with an approved fungicide. Call Plant Information at (847) 835-0972 for recommended fungicides and timing.

Fruits and veggies

h Plant small transplants of asparagus, carrots, cauliflower, lettuce, mustard, onions, peas, early potatoes, radish, rhubarb, turnips and all other cool-season crops as weather permits.

h Plant midseason potatoes in mid-April.

h Later in April, begin to harden off warm-season vegetable transplants in a cold frame, or take flats of transplants outside to sunny protected areas, moving them indoors at night.

h Plant strawberries and pinch off first-year flowers to develop strong root systems.