Prune azaleas immediately after they have finished blooming or tried to bloom. The new flower buds form in late spring and early summer. Azaleas should not be pruned as a hedge. This leads to poor air circulation and can lead to disease problems. It is best to cut off shoots that are growing out too far and remove all dead wood inside the plant. You should try to get good air flow through the plant.

Having said this, I have seen the Japanese shear their Satsuki Azaleas into a hedge and maintain it meticulously all year. However they don't use hedge shears. They prune each branch separately with hand shears. They would rather have a manicured green azalea than a shaggy flowering one. Different tastes ...

There is a group of azaleas called Enchore Azaleas that some people grow in your area that bloom on old wood and then bloom again in mid summer on new wood. Encore Azaleas require very little pruning to retain good form and do not need "dead-heading." If you think an Encore Azalea needs pruning, do so immediately after the spring flowering for maximum bud set. Light pruning of more established plants will stimulate growth and flowering.

Here is a link that might be useful: Encore Azaleas

Thank you Rhodyman,
Encore azaleas sound amazing! I will definately plant one in my garden.
Really appreciate you advice. Thanks again!
~Natalie

i would like to know when is the best time to fertilize azaleas and rhodendrons, and should i pinch back the rhodendrons, thank you

The best time to prune azaleas is right after they finish blooming. As with most spring bloomers, azaleas start to form the next year's flower buds in mid summer and by fall the buds are fairly well developed. Pruning after mid summer removes the next year's flower buds. Do not pinch after June because then flower buds will not have time to develop for the following year.

Unlike other shrubs in the landscape, azaleas are shallow rooted and can be easily injured by excess fertilizer. In fact, some experienced azalea growers do not apply chemical fertilizes at all. They have found that plants usually can obtain sufficient nutrients for growth and flowering from the organic matter added to the planting hole and from the decaying mulch on the soil surface.

Azaleas grow well naturally at relatively low nutrient levels. Therefore, fertilization should be done carefully, or the fine, delicate roots close to the soil surface will be damaged. A fertilizer analysis similar to 6-10-4 applied at 2 pounds per 100 square feet to the soil surface is usually adequate. If you use a good commercial fertilizer like HollyTone, apply at half the rate on the package. Cottonseed meal is also a good fertilizer.

Fertilizing outdoor plants should be done in May, but not after July 1. Late summer fertilization may force out tender fall growth that will be killed by the winter. Broadcast fertilizer over an area extending from the trunk to 4 to 6 inches beyond the dripline or edge of the canopy. Be careful when broadcasting fertilizer over the top of plants, because the fertilizer granules may collect in the leaf whorls and cause foliar damage as it dissolves. Always fertilize when the foliage is dry, then use a broom or rake to brush residual fertilizer from leaves or stems. Apply overhead irrigation soon after application to wash any residual fertilizer from the foliage and to dissolve the fertilizer applied. Do not remove the mulch when fertilizing. The fertilizer will move through the mulch with irrigation water and rain.

Coming to this discussion a little late...

Where I get confused with azaleas in late summer/September, is what to do with the long new growth that is about a foot taller than the main body of the bushes.

If I trim this new growth now, will I be spoiling next spring's bloom? What's the best way to keep azaleas looking shapely after spring pruning?

Hi Idixierose

The best solution is to buy varieties that don't do this. This is a definite disadvantage of certain varieties. Once you have a variety that does this, it is best to wait until after it blooms and then cut it back. It will look bad, but if you don't wait it won't bloom, so it is a gotcha.

When you do cut it back, you can cut most anywhere since though you may not be able to see them, these plants have dormant growth buds nearly everywhere.

Most of my plants are setting flower buds for next year already so I am not going to do any pruning now.

Here is a link that might be useful: How to care for azaleas

Thanks Rhodyman.

I'm an estate gardener and the garden I tend was established in the 1920-30s. Most of the older azaleas are Southern Indicas -- lots of Formosa, Gerbing, Taber, among others. Not exactly practical to replace them.

What I've been doing is just clip the long shoots where they are eyesores and try to avoid trimming as much as possible.

Given the swarms of mosquitoes up in the azalea beds, I'm looking for any excuse to avoid trimming azaleas.

You want to trim them right after their spring bloom. Most of next year's bloom are set by the middle of the summer.

Here is a link that might be useful: best time to trim azaleas