Fertilize Trees for Healthy, Vigorous Growth

Fall is a great time to fertilize trees. Trees that have grown less than six inches in the past year, or have smaller or yellowing leaves may benefit from fertilization. Broadcasting the fertilizer is easier, and just as effective as digging holes around the root zone.

Produced by K-State Research and Extension, Department of Communications. For more information, visit our website at: http://www.kansasgreenyards.org

Transcript:
Fertilize Trees for Healthy, Vigorous Growth

If you have a yard that is well fertilized, such as a fescue yard, and you fertilize your lawn once or twice a year, that’s enough for the trees, too. You won’t need to give them anything extra. But, trees in an unfertilized area, such as this buffalo grass and bermuda area, will need fertilizer to help the trees grow.

We usually use only nitrogen, unless the lawn is deficient in phosphorous or potassium. Since this site is low is phosphorous and potassium, we’ll be using those nutrient, too. We’re using a 13-13-13 fertilizer, which is even amounts of nitrogen, phosphorous, and potassium.

We’re going to use it at the rate found in the K-State publication titled “Fertilizing Trees in the Landscape,” which you’ll find online. On small trees, we’ll use about 2 ½ pounds, and a larger tree we’ll use about 5 pounds on the tree.

The roots are out about twice the spread of the leaves on the tree. So, on this tree, the limbs are about five to six feet out from the trunk. We’ll need to fertilize at least 10 feet out beyond that. According to the chart we’re using, on a larger tree, we’ll be going fifteen feet out from the tree – or a thirty foot diameter – all the way around the tree.

There are two different types of spreaders. Drop spreaders, which drop it straight down, and broadcast spreaders, like this one, that tosses it out. This type of spreader will spread it about three feet in each direction.

Some people will fertilize too much up close to the tree. We’re going to go out about fifteen feet from the tree. We’ll go once around the tree… twice….shake it up a little bit, and three times – each circle gets bigger around the tree. Sometimes you’ll have a little bit left in the spreader, so, just take it out and finish spreading the fertilizer with your hands.

This feature story prepared with Bob Neier, former Kansas State University Research and Extension Horticulture Agent, Sedgwick County. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.