After azaleas and rhododendron plants have had time to settle in where you've planted them (see Page 3), the next step in caring for these bushes is fertilizing. But even then, be careful not to over-fertilize. Stay away from the mentality that says, "If some fertilizing is good, then more must be better." There are standard fertilizers to use on azalea and rhododendrons bushes -- mixes that can be purchased at nurseries and major hardware chains. Follow the instructions on the fertilizer's label. Except perhaps for one instruction -- the amount of fertilizer to apply. Cut that in half. It is usually better to be conservative about applying fertilizer.
A good time to fertilize azaleas and rhododendrons is right after they have finished blooming.
Ally #1 in Azalea, Rhododendron Care: Mulch
Mulching is an essential part of proper care for azalea bushes and rhododendrons. The roots of these shallow-rooted plants need the protection that mulch affords against extremes of heat and cold -- and against drying out. Remember, the fact that these plants like a well-drained soil doesn't mean they like to be dry. Azaleas and rhododendrons are not desert plants; they like water. They just don't like to be sitting in it for long periods of time, which would cause their roots to rot.
The best mulches for azaleas and rhododendrons are acidic mulches, such as pine straw (although, as I report in the following article, some experts now dispute some aspects of the concept "acidic mulches"). For information on other acidic mulch choices, please consult Choosing the Proper Mulch. Since mulch eventually does break down and become a component of the underlying soil, you might as well go with an acidic mulch. There's no sense in fighting the acid-loving tendencies of azalea and rhododendron plants.
Pruning Azaleas, Rhododendrons
Pruning azaleas and rhododendrons should be undertaken immediately after they finish blooming (usually June or July). Pruning the bushes later than that risks interfering with the development of next year's buds. Begin by pruning off dead or injured branches, which could cause disease and insect problems in the future. Then prune back tall, gangly limbs shooting out of the top of the bush. This will promote a more attractive, compact shape.
A proper regimen of pruning azaleas and rhododendrons, in conjunction with the other care tips offered above, will help these flowering shrubs provide your landscape with eye-opening hedges or specimen plants for years to come.