Encore Azaleas are unique in that they bloom in the spring and fall, and sometimes in summer. So when is the best time to prune them? Encore Azaleas do not have to be pruned, or their flowers deadheaded. That being said, they respond very well to pruning and, in fact, will benefit from it.
Unlike most other types of azaleas, which only set flower buds one time a year during fall and then bloom in spring, Encore Azaleas produce buds every time new growth is produced. So, pruning Encore Azaleas immediately after the spring bloom cycle will encourage more new growth, and consequently more flower buds. Then, sometime during summer, these new buds will begin opening and continue doing so through fall. For azaleas, this is quite an amazing phenomenon.
The next question might be: Should I prune my Encore Azaleas after the the fall bloom cycle? The answer is: no. Why? Because you want to avoid stimulating new, tender foliage that might be damaged or killed by an early frost or freezing temperatures. This kind of cold damage can cause stress the plant. So, to avoid problems, cease pruning Encore Azaleas two months prior to the usual first frost date in your area. In the South (Zones 8-10) this means September. Further north (Zones 6 and 7) this might mean August. Find your USDA Zone here.
TIP: Fertilizing Encore Azaleas after the spring bloom cycle pruning will help to promote overall health and vigor, and more new growth, which means more flower buds. I feed my azaleas with a product called Nitroganic Fertilizer, which is a "goof proof" organic fertilizer that contains 3% naturally occuring iron and helps to keep the deer away that live on the property next door. But any good Azalea, Camellia, & Rhododendron type fertilizer will do. Azaleas prefer an acid soil so make sure the fertilizer you choose contains extra-added sulfur and/or iron. This will help keep the foliage nice and dark green and increase flower production.
How To Prune Encore Azaleas
When pruning a healthy Encore Azalea, use sharp hand pruners to cut back branches that have outgrown the rest of the shrub and are spoiling the shape of the plant. Cut these branches back to a point just a couple or few inches above the main form of the plant. Make your cuts about an inch or so above a leaf.
TIP: Avoid using hedge trimmers to prune your Encore Azaleas. Doing so will cut leaves in half, leaving your azaleas with an unsightly appearance. A pair of sharp hand pruners, also known as bypass pruners, works great for selective pruning.
Rejuvenation Pruning of Old Azaleas
Rejuvenation pruning is a technique most often used to restore older, tired and thinned out plants to health. When using this pruning technique on azaleas, it involves cutting the branches of the shrub back to short stumps. This is the only way to remove all of the old wood and provide the plant with one hundred percent juvenile wood loaded with leaf buds and, in the case of Encore Azaleas, flower buds.
When and if your Encore Azaleas require rejuvenation pruning, there are two basic methods for doing so. You can cut the overgrown shrub back in one fell swoop, or spread the pruning out over several seasons.
One Fell Swoop...
If you choose the all-at-once approach, cut all the branches back to 6-12 inches above ground level in late winter or very early spring, right before they would ordinarily flush out with new growth in spring. When using this method, do not feed the azalea after pruning. After pruning, the shrub will typically grow a fair amount new growth in the first year but may not start to produce blooms again until the second year. By the third or fourth year after the pruning the shrub should be of a fair size and have a nice, compact shape. From this point on, you can prune it lightly as normal.
The more gradual approach to rejuvenation pruning involves spreading the process over a three year period; cutting 1/3 of the stems to within 6-12 inches of the ground at the beginning of each growing season. By the end of this time, all the old wood will be removed and only healthy new growth will remain. When using this method, you can feed as normal after pruning.