This article appeared in the April 2002 web issue of Horticulture Update, edited by Douglas F. Welsh, Ph.D., and produced by Extension Horticulture, Texas Cooperative Extension, The Texas A&M University System, College Station, Texas.
Garden Checklist for April, 2002
Dr. William C. Welch, Landscape Horticulturist
Texas A&M University, College Station, Texas
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. Cottonseed meal, alfalfa meal and composted manures are organic sources of fertilizer that work well on roses.
Climbing hybrid tea and other 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. Donít over fertilize, as azalea roots are near the surface and damage can occur. When calculating fertilizer needs, split the total amount into 3 equal amounts and apply each portion at two week intervals. 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.
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 those 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 brought into the yard through contaminated soil sources.
Watch newspaper and other publicity for information regarding wildflower trails and gardens. Plan to take a trip to enjoy these beautiful natural resources.