Plant Health Care -- Fertilization and Aeration

Fertilization is an important aspect of mature tree care. Well-nourished trees and shrubs have better resistance to disease, insect attack and drought. Fertilizing a tree can improve growth; however, if fertilizer is not applied wisely, it may not benefit the tree at all and may even adversely affect the tree. Our licensed arborists can determine which nutrients are needed and apply the appropriate fertilizer correctly.

Chances are, the trees your landscape are actually in a foreign environment that lacks the nutrients found in the rich layer of humus occurring naturally on the forest floor. This means that your trees' roots must reach out to obtain the nutrients they need, often extending to two to three times the size of the leaf canopy. If you use a lawn fertilizer, we recommend not using a version that also kills broadleaf weeds because the herbicide in it will be picked up by the broad-leafed trees, and may harm or kill them. Our tree experts can help you find where your tree’s root system extends.

When soil becomes compacted, it becomes difficult for water and air to reach the roots of the trees. When you have over about one-half inch of thatch in your lawn, water and air also have a difficult time reaching the roots of your trees. Aeration is the process of carefully making small holes in the ground so that air and water can better reach the root system.

Deep-root feeding can be done in conjunction with aeration. Deep root feeding puts the nutrients well below the soil level, where the tree will make best use of them. This means that you will not affect your lawn or shallow-rooted shrubs, which may require a different kind of fertilizer.

Cotta Tree Service recommends that your trees be fertilized and aerated before they show the effects of nutrient deficiency, before the tree’s growth is stunted or the tree’s resistance to disease and pests is reduced.


Cotta Tree Services has been serving the towns of Darien, CT; New Canaan, CT;  Stamford, CT and Norwalk CT since 1929.