Fertilizing Ornamental Trees & Shrubs
Fertilize when shrubs and trees are actively growing. In most areas of Mississippi, the best times to fertilize are from April through October. In the Gulf Coast counties, the best times are from March through October. Young plants are small and growing actively, and they require more fertilizer than mature, established plantings.
Mature, Established Plantings
Well-established shrubs and trees approaching maturity benefit from an annual application of fertilizer in early spring (March 15 through May 30). Mature plants in extremely sandy soils may need an additional application in late summer (August 15 through September 15).
Don’t fertilize newly transplanted trees and shrubs for at least 4 weeks after planting. By this time, the root system is growing and can absorb nutrients to stimulate new growth and encourage rapid development. Fertilize young plants at several regular intervals during the first, second, and third growing seasons. After the third growing season, reduce the fertility program to one annual application.
Fertilizer Sources and Rates
Complete fertilizers containing nitrogen, phosphorus, and potassium (potash) can be used on trees and shrubs. These fertilizers (or any fertility addition) introduce nutrients into the environment. Take care to avoid overapplication. Phosphorus and potassium may not be needed in your soil. Base the fertilizer application rates on current soil tests. Follow the chart with this publication to select a fertilizer. You must control soil erosion and water runoff to minimize potential nutrient loss. Information on soil testing is available at your county Extension office or visit this website's Soil Testing page.
Where To Place the Fertilizer
The easiest way to apply fertilizer is by broadcasting (spreading evenly) the material on the soil surface of the planted areas. The active root zones of ornamental trees and shrubs include all the soil area from the trunk out past the foliage canopy and often beyond.
|Kind of Planting||First Application||Second Application|
|Newly planted trees and shrubs
(established less than 3 years)
|Beginning 4 weeks after transplanting or March 15 through May 3||August 15 through September 15|
|Matuer trees and shrubs (or plants established for 3 years or more)||March 15 through May 30||Usually not needed unless soil testing indiates deficiencies|
*Ater the plants have been established for 3 eyars, consider the planting well-established, and fertilize as for mature trees and shrubs.
How To Apply Fertilizer
Using any type of fertilizer spreader is better than broadcasting by hand. There are many types of spreaders available from retailers, and a homemade spreader is easy to make. An empty coffee can with a plastic lid makes an excellent fertilizer applicator. Cut holes in the plastic top to make a shaker. Measure and weigh the material needed for your planting area. Place the fertilizer in the can and apply it to the appropriate square footage of planting area. In most cases you must refill the can several times to apply all the materials needed.
Apply the material only when the soil is dry. Make sure the foliage and stems of the plant are dry, too. Always apply the fertilizer evenly. Do not let fertilizer fall on nonsoil areas, such as sidewalks or streets. Avoid a concentrated ring of fertilizer around any shrub, because this could cause root burn. Avoid placing fertilizer in direct contact with the foliage or the main trunk of the plant.
After applying fertilizer, water the plants and soil thoroughly. This will dissolve most of the material and carry it into the root zone where it can be absorbed. In addition, it can help avoid burning roots near the top of the planting area. Never use more than the recommended rate.
Recommended Fertilizers and Rates
(lb/100 sq ft of soil area)
|5-10-5||1 1/2 to 2|
|6-8-8||1 to 1 1/2|
Numbers higher than 10-10-10 not recommended. One quart of complete fertilizer (6-8-8, 8-8-8) weighs 2 pounds.
Examples (Using 8-8-8 Fertilizer)
|A||10 ft||x||4 ft||=||40 sq ft||x||1 lb/100 sq ft||=||0.4 lb|
|B||10 ft||x||5 ft||=||50 sq ft||x||1 lb/100 sq ft||=||0.5 lb|
|C||10 ft||x||12 ft||=||120 sq ft||x||1 lb/100 sq ft||=||1.2 lb|
|D||30 ft||x||5 ft||=||150 sq ft||x||1 lb/100 sq ft||=||1.5 lb|
|Total Needed||=||3.6 lb|
Information Sheet 0411 (POD-01-16)
Distributed in Mississippi by Dr. Geoff Denny, Assistant Extension Professor, Plant and Soil Sciences.