April 2006
Victoria County Master Gardener Association
Ground rules and tools

April 6, 2006
GAIL DENTLER - Victoria County Master Gardener

With spring officially here, this is the time to focus on planting your landscape and taking care of your lawn. Today's article follows two others published the past two weeks that discussed choosing, maintaining and mowing turfgrass. They are archived on the Master Gardener Web site at http://community.victoriaadvocate.com/groups/VictoriaCountyMasterGardenerAssociation.
Scroll down and click on Gardeners' Dirt (January - March 2006) for easy reference.

In April gardeners can readily spy the fruits or flowers of our labor in March. One area we want to stress this month is managing St. Augustine turf.

First, a test

It is recommended that every three years a soil test be taken to assure success in maintaining your lawn.

If you haven't taken a soil test, it is recommended that you use a fertilizer that contains nitrogen only (21-0-0), known as ammonium sulfate, or one that is low in phosphorus.

Without a soil test, research has shown that the nitrogen fertilizer application on St. Augustine should range from 3 to 5 pounds of actual nitrogen per 1,000 square feet per year.

Fertilizers provide plants and soil with nitrogen, phosphorus and potassium; these three are known as macronutrients. These help the plants to grow and flourish which produce better results for the homeowner.

The 'green' light

A fertilization schedule is required for a healthy lawn.

Begin fertilizing three weeks after the grass turns green and when there is little chance of a late frost. This may be in March through May for the entire state from Brownsville to Lubbock, but for our area the best time to start is to wait until mid-April.

So, for starting the year, apply 3/4 to 1 pound of actual nitrogen per 1,000 square feet of lawn. If you use 21-0-0 fertilizer, it is 21 percent nitrogen so divide the recommended rate (3/4 or 1 pound) by the fertilizer nitrogen strength (0.21) and the rate to use is 3.6-4.7 pounds of 21-0-0 per 1,000 square feet. That is not much!

You also may use a 21-7-14 fertilizer or a slow-release version of this at the same rate but the reason we are recommending the 21-0-0 to be used if you didn't do a soil test is because too many yards are building up the phosphorus level (the second number) and causing plant growth problems. Remember, to prevent disease it is recommended to not over-fertilize and always use less if your yard is green enough. This can be added again in June if needed for maintaining a green color and at half the rate in October.

Do not fertilize St. Augustine grass from December through February unless the lawn has been overseeded.

Feed flowers, too

Other areas to fertilize this April would include your roses, azaleas and camellias. As camellia and azalea plants finish blooming, fertilize them with 3 pounds of azalea-camellia fertilizer per 100 square feet of bed area; this contains an acidic type fertilizer. Also, with azaleas be careful on the amount given because the bush's root system grows close to the surface and too much fertilization will damage the plant.

Roses are another plant to fertilize this month. Use a complete fertilizer for the first application as new growth starts then use ammonium sulfate or a high nitrogen source every four to six weeks after that.

Check roses for black spot and use a spray containing triforine, commonly known as Funginex. It is recommended to use this every 7-10 days, but if it stays dry and rains are infrequent, minimize the use of fungicides.

Prune any climbing roses after they flower. When applying fertilizer, if it is a spray, apply on the soil around the base of the plant. This will allow the root structure to gain nutrients.


Other gardening tips for April consist of pruning those spring flowering shrubs, Indian Hawthorns and azaleas. Keep in mind the shape of the plant and avoid excessive cutting.

One must begin the awful task of weeding. Weeds can cause delays of flowering plants if not taken out of the garden and left to live in the beds. Mulch helps to discourage weeds and for those that survive this process it makes them easier to pull out.

Some bugs to identify in the garden are aphids and bagworms. Aphids are 1/16 to 1/8 inch in length and they vary in color and shape. They populate the underside of leaves. Aphids can be eliminated by spraying with a strong stream of water. If this doesn't work you can use an insecticidal soap solution. Some like to release a ladybug to take care of those aphids. If the aphids are strong on trees, then an approved pesticide that is stronger in formula may be what you need and can be recommended by the Extension office.

Look for bagworm attacks on junipers or other narrow-leafed evergreens. They are brown bags that hang from tree or plant branches. It is recommended to use the very safe Bt insecticide or Sevin dust or spray. You have a chance to control this pest if you apply when the insect and bags are about 1/2 inch or smaller in length. A large infestation of these can kill a tree.

Plan your color

This is a great time to begin sowing seeds into the beds. Plants that can handle this are amaranthus, celosia, cosmos, marigold, portulaca and zinnias. Keep the area moist until seeds germinate. If you don't like working with seeds because you want instant color then find annuals of petunias, dianthas and begonias to place in your beds. When you are planting these be sure to pinch off flower buds to give an opportunity for them to establish their roots.

Plant sale

On Saturday, April 22, you can shop the master gardener plant sale for other spring plantings, beginning at 8 a.m. at the 4-H Activity Center at Victoria Regional Airport.

Veteran shoppers can tell you that there are great buys on plants nurtured from Master Gardeners' own green thumbs. Mark your calendar now - those who come later in the day miss the best selections.

Call the Extension Office at 361-575-4581 for more information.

The Gardeners' Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas Cooperative Extension-Victoria County.