When you bought that azalea it was thick and full, right? Then three or four years later you see that above that bushy layer of foliage and flowers there are suddenly tall sticks that are bare, with green growth only on the top of those stems. Your azalea is getting thinner and “leggy” and you don’t know what to do in order to make it bushy again.
Unfortunately many think that fertilizer is the answer, and this only make the plant grow larger and higher instead of fuller. What’s a gardener to do? The answer is simple: Snip the new growth as the flower fade. If you cut the new growth in half just as it is growing it will keep the plant fuller and it will still flower next spring.
If your azalea has tall, bare stems that shoot over the bushier growth you can cut those off now. From now on, however, snip that new growth as the shrub is flowering or the blooms are just beginning to fade.