Montgomery column: Keeping azaleas beautiful, blooming
Few plants can rival the spectacular floral displays that are seen in azaleas (Rhododendron). The profusion of flowers, the vivid colors that are available, and their adaptability to different soil and climates makes them one of the most popular shrubs that we grow. It would not be springtime without azaleas, and this is especially true in the Southeast.
Most well-established neighborhoods with their large trees are the ideal cover for these lovely plants, giving them the dappled shade they need and the leaf litter and pine needles that azaleas appreciate. They have been bred for hundreds of years and there are more than 10,000 different cultivars of these lovely plants. Although most people associate azaleas with spring, some bloom in summer and fall. By carefully selecting plants, you can have azaleas blooming at least eight months of the year.
To keep these plants looking pretty and blooming their heads off, one needs to do some general maintenance after they bloom, and timing is critical if you want your azaleas to bloom next year. The best time to prune is within three to four weeks after they finish blooming in the spring. Azaleas, like other plants, need time to make the flower buds for the next year. If you wait too late to prune, you will be cutting off the flower buds for the following spring and instead of having a lovely flowering plant, you will have a green bush with few flowers, if any at all.
There are two classes of azaleas, our native azaleas and the Asian azaleas. Native azaleas are indigenous to many parts of the U.S. and they are growing in popularity. They are sometimes called wild or honeysuckle azaleas and many have a lovely fragrance. These azaleas typically do not need to be pruned because they have a more open shape. However, if you do want to prune them, it is very important to prune at the right time so that you do not miss out on flowers the following year.
On the other hand, the Asian azaleas are the evergreen ones with most of them coming from Japan. Azaleas bloom on old wood. They produce flower buds on last year’s growth and for this reason, it is very important to prune immediately after they finish blooming. If you prune in summer or fall, you will be removing the flower buds. The new reblooming azaleas like Encore and Bloom-A-Thon bloom on both last year’s growth and the current year’s growth. They also need to be pruned in the spring, like the other evergreen azaleas.
When preparing to prune, you need a pair of hand clippers and a pair of loppers. Hand clippers work well on the smaller branches and use the loppers on branches one-half to 1 1/2 inches thick. The long handles of the loppers give you the leverage for cutting larger limbs and allows you to get inside the bush to prune.
I would not use hedge trimmers or shears on azaleas unless you want a formal look or a shaped hedge. If you do this year after year, you will still need to go deep inside from time to time and prune. If you only use hedge trimmers, over time, you will have only growth on the very top of the bush and the plants could become leggy.
In most landscapes, azaleas look best when they are pruned a little each year to let light and air get into the bush yet keep the graceful shape of the bush. This is done by going inside the bush and pruning. I have a rule that I never prune more than one-fourth to one-third of a bush in any given year. You can come back next year and prune again so the bush keeps a lovely shape.
However, if major pruning is needed, and you want to take out more than one-third of the bush, it is best to do this in the late winter. This is only needed when a bush has become overgrown and you want to make it smaller in size. You can cut a bush down to about 18 inches in height but this dramatic pruning must be done in winter when the sap is down. Of course, you will be losing blooms that spring but this way, you will save the bush and it will come back and you can work to keep it under control. I find that larger azaleas, like the Southern Indica azaleas, are the ones that need this pruning if left unpruned year after year.
People are often scared to prune and I can understand this fear. I use to be the same way. What I find is a good solution is to prune some and then go back a few days later and see what you think. You can always cut more if the shrub is still too large. Just remember not to cut more than a quarter to a third of a bush when doing spring pruning.
Recently, I pruned one bed and it looked thin in some places. Looking at that bed several days later, branches were starting to fill in where I had cut and it looked much better. Branches that were squashed had moved over to fill the holes. It makes me think that I need to go prune some more. Plants are forgiving too and they will put out new growth and hide your mistakes.
Betty Montgomery is a master gardener and author of “Hydrangeas: How To Grow, Cultivate & Enjoy,” and “A Four-Season Southern Garden.” She can be reached at firstname.lastname@example.org.