Fertilizing Trees

By Sean Stowell, regional editor

By ?EUR??,,????'??broadcasting?EUR??,,????'?? or evenly spreading fertilizer, trees will show large leaf size and retention along with large twig and branch elongation and retention.

Every good landscape has trees at its core. A tree that is well taken care of more than pays for itself in the long run. Proper fertilization is especially important to landscape plants in urban and suburban environments.

According to the Virginia Polytechnic Institute and State University Cooperative Extension, modern building methods create adverse growing conditions for plants. Good topsoil gets removed and not replaced, and heavy machinery scrapes and compacts fertile soil, reducing its aeration and drainage.

Trees are autotrophs; they get nutrients from the sugar produced in their leaves, or store it as starch for future needs. While most soils have enough nutrients for trees it may be a good idea to get a soil analysis done before you fertilize. According to the St. Lawrence Community Forestry program, trees adjust their growth and development rates to the level of nutrients, and will usually make out all right as long as the roots can continue to grow.

Proper Nutrients

Be sure to look for yellow leaves, reduced leaf size and retention, premature fall coloration and leaf drop and overall reduced plant growth and vigor. To help combat this, start a fertilization schedule using slow-release fertilizers. They work best when applied in early fall or early spring. The roots will use the fertilizer in the fall and by the roots and shoots in the spring. If you work in the northeast standard fertilizers should be applied in late May or the early part of June.

Determine a plant?EUR??,,????'???s root zone by doubling the amount of feet the branches of a tree appear to spread from the trunk.

It is also important to apply the correct amount of fertilizer. It is recommended to apply fertilizer over the entire root zone of a plant. To determine a plant?EUR??,,????'???s root zone, you must know the radius of the roots. The root radius is at least twice the radius of a plant?EUR??,,????'???s crown.

Here?EUR??,,????'???s an easy way to figure that: If a tree?EUR??,,????'???s branches spread 15 feet from the trunk, the roots spread 30 feet. The Virginia Cooperative Extension gives the following formula for finding the total square feet:

3.14???30 (root radius) x 30 (root radius)= 2,826 sq. ft.

Once this is figured, you can estimate the amount of fertilizer needed. It is advisable to use about two pounds of fertilizer per thousand sq. ft. Be sure to spread the material over the entire root zone. Also, dig holes throughout the root zone and fill them with fertilizer. It doesn?EUR??,,????'???t work because most feeder roots are in the upper layer of the soil.

So now you have an understanding of three important aspects of tree care. Good luck and remember to make sure the root ball gets wet, use the right amount of fertilizer, and keep in mind those aphid midges are there to help your trees.

Tree Facts

2.3 billion ?EUR??,,????'??? Number of land acres in the United States.

286 million ?EUR??,,????'??? Number of acres dedicated to parks, wilderness, wildlife, and related uses in the United States. Source: ers.usda.gov