Lawns

Fertilizing lawns properly involves two major considerations. First, what species is being grown? Centipedegrass needs low levels of fertilizer. St. Augustinegrass and other lawn species need more moderate fertilizer levels. Second, the nutrient status of the soil is important. For a general statement, the important time to fertilize a lawn is mid-spring after growth is initiated (most people say after 3-4 mowings). A rate of no more than 1 pound of actual nitrogen per 1,000 square feet of area is recommended.

Trees

Tree fertilization can be done many ways. Old recommendations for tree fertilization were based on the age of the tree or the diameter of the trunk. The new recommendation is to fertilize based on the root zone area. Detailed information on these procedures is available in the publication “Trees for Louisiana Landscapes – A Handbook.”

Shrubs

All growing plants need a steady supply of nutrients or essential elements for optimal growth and development. Usually no fertilizer is added at planting time because adequate fertilization is provided to the plant at the nursery. After shrubs have gone through one growing season, the first fertilizer mixture containing nitrogen, phosphorus and potassium should be applied in late winter or early spring. Additional fertilizing may be beneficial at one or more times during the growing season (usually in June or early July and in late summer or early fall – August or early September). For early flowering shrubs, initial fertilizing should take place in spring after flowering has occurred. One to 2 tablespoons of the following examples are adequate for each plant (more than this may cause damage): Osmocote® 14-14-14 or StaGreen® Nursery Special 12-6-6. Both of these products releases over a three- to four- month period. The amount of fertilizer to apply varies with the age and size of the plant, native fertility of the soil and the quantity and type of organic matter supplied. In general, the first application, 2 to 4 pounds of a complete fertilizer should be applied for each 100 sq. ft. of growing area. For individual shrubs, apply 1/8 to 1/4 pound (1/2 to 1 cup) of a complete fertilizer per plant. Small plants should receive half this amount. The newest recommendations suggest applying 1 to 2 pounds of actual nitrogen per 1000 sq. ft of bed area.

Ground Covers

Fertilize ground covers once a year. A recommended rate is 1-2 pounds of actual nitrogen per 1,000 square feet of planted area. Use a slow-release fertilizer as a BMP (Best Management Practices) tool.

Annual and Perennial Flowers

Begin a fertilization program at planting. A complete slow-release fertilizer can be incorporated into the landscape bed before planting, or it can be broadcast over the bed after planting. Apply at the recommended rate. Light applications of a water-soluble fertilizer can be made at planting and at regular intervals thereafter, but are not needed when a slow-release fertilizer is used properly. Avoid using 8-8-8, 13-13-13 and similar fertilizers in your flowering annual beds. These do not provide the ideal response desired, and they need to be applied much more frequently than do slow-release formulations. Remember that excessive fertilization leads to excessive plant growth and results in fewer flowers.

BMP Checklist:

• Identify the plants and know their fertilizer requirements.
• Select slow-release fertilizers that release over a 3 to 4 month period (or longer).
• Know the measurements of the area that will be fertilized and apply a proper rate.
• Irrigate following fertilizer application.