Follow these basic principles to promote healthy growth in trees. Because most trees can fend for themselves pretty well, caring for trees is one of the less technical and complicated subjects for gardeners.
Watering: Slow Is Better
Thoroughly water a tree's entire root zone during periods of drought with the equivalent of 1 inch of water, once every week or two, depending on soil type. Apply water slowly to prevent runoff, and ensure that the water reaches the tree’s deep root system. An irrigation or soaker hose is great for this type of watering, as the water will leak slowly through the hose wall.
Fertilizing: Deep Root vs. Surface Application
Trees have been traditionally fertilized by creating holes in the root zone and pouring in dry fertilizer. Some arborists use probes to inject liquid fertilizer into the root zone. The placement of fertilizers need to be where the tree can get them, so don't place them too deep. Most tree roots are within 12 to 18 inches of the lawn surface. As always, follow all instructions on the fertilizer packaging.
Pruning: Trimming Trees at the Right Time and Place
Because there are so many different types of trees, it’s impossible to list every pruning technique here. Here are a few helpful suggestions for the most common types of trees: