Your lawn care professional is able to make sure that your trees and shrubs get the same level of care that your lawn will receive. Usually trees and shrubs get much of the nutrients they need from the fertilizer that is put on the lawn. Unfortunately, this means that the lawn will be losing some of the nutrients that it needs to grow and be healthy.
Fertilizing trees and shrubs ensures that both they and the lawn get all the nutrients that are required. The same principle applies to ground covers that may share the same space as trees and shrubs. Your lawn care professional will give each element of your landscape design the exact balance of nutrients that it needs to be healthy and flourishing. This is especially important in flowering and fruit bearing varieties of plants and trees.
Trees and shrubs planted next to driveways or sidewalks naturally can’t get any nutrients through the concrete or asphalt. This can give rise to deficiencies that will be compensated for by fertilizing.
Also, consider the retained radiant heat built up by direct sunlight on the pavement. This heat robs much of the water and moisture from the soil and the trees or shrubs will require more watering.
There are two ways to tell if your tree needs fertilizer. The easy way is to simply look at it. A light green or yellow-green color indicates that it is short on nutrients.
Another indication is if it has a lot of dead wood,sparse foliage, or if the new growth is shorter than it should be. Dark green leaves and excessive growth of new shoots means you can delay fertilizing for another year.
When necessary, DEEP ROOT FEEDING allows the fertilizer to be delivered right into the tree’s root system.
A slow-release fertilizer is used since it will not burn the roots. It can be distributed evenly around the tree in holes drilled about one foot deep and two feet apart. The holes are drilled to a point that is six to eight feet beyond the width of the canopy.
Deciduous trees and shrubs have a special need for nitrogen. They should be fertilized in either the early spring or late fall. This will keep the height of their growing season in mid-summer and will protect the plants from sustaining damage to new growth as the winter approaches.
Plant beds that have organic mulches also require an extra measure of nitrogen fertilizer. The decomposing materials in the mulch compete with the plants for their nitrogen supply.
thanks to University of Illinois for information provided