Garden Checklist for April 2000

By Dr. William C. Welch
Professor and Landscape Horticulturist

Prune spring-flowering shrubs soon after flowering. Keep the natural shape of the plant in mind as you prune, and avoid excessive cutting except where necessary to control size.

Roses have high fertilizer requirements. For most soils, use a complete fertilizer for the first application just as new growth starts; then, use ammonium sulfate or other high-nitrogen source every 4 to 6 weeks, usually just as the new growth cycle starts following a flowering cycle.

Continue to spray rose varieties susceptible to black spot, using a spray containing triforine or, as it is more commonly known, Funginex. Use every 7 to 10 days.

Climbing roses may be pruned as soon as they complete flowering.

Removing spent flowers, trimming back excessive growth, and applying fertilizer to an established annual bed can do wonders towards rejuvenating and extending the life of the planting.

As soon as azaleas have finished flowering, apply an acid type fertilizer at the rate recommended. Don't over fertilize, as azalea roots are near the surface and damage can occur. Water thoroughly after fertilizing.

Seeds of amaranthus, celosia, cosmos, marigold, portulaca, zinnia, and other warm-season annuals can be sown directly in the beds where they are to grow. Keep seeded areas moist until seeds germinate. Thin out as soon as they are large enough to transplant. Surplus plants can be transplanted to other areas.

It will soon be time for bagworms to attack junipers and other narrow-leafed evergreens. Control measures, such as Sevin dust or spray, should be applied while the insects and the bags are about one-half inch in length.

For instant color, purchase started annual plants. Select short, compact plants. Any flowers or flower buds should be pinched, to give plants an opportunity to become established.

Check new tender growth for aphids. A few can be tolerated, but large numbers should be controlled. Always follow label instructions on approved pesticides for control.

Many flower or vegetable seeds left over after planting the garden can be saved for the next season by closing the packets with tape or paper clips, and storing in a sealed glass jar in your refrigerator.

Start weeding early in the flower garden. Early competition with small plants can delay flowering. A mulch will discourage weed growth, and make weeds that do come through easier to pull.

Soil purchased for use in beds, low areas, and containers should be examined closely. Often, nut grass and other weeds, nematodes, and soilborne disease are brought into the yard through contaminated soil sources.

Watch newspapers and other publicity for information regarding wildflower trails, and plan to take a trip to enjoy this beautiful natural resource.

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