By Allen Owings
Are some of your Encore® Azalea varieties growing larger than expected? Are they growing well, but getting thin in the center? Are some large, but not as vigorous as they have been in the past?
Re-blooming Encore® Azaleas do not have the tendency to outgrow their planting area as much as the spring-blooming Southern Indica varieties. But, if they do, rejuvenation pruning may be a way to “gain control” and return the plants to a form and shape that suits your landscape situation.
Rejuvenation pruning, sometimes called renewal pruning, is used to restore and reinvigorate older shrubs that have “thinned out” over time. Hollies and gardenias are other shrub candidates for this pruning method. This major pruning may be a shocking experience for many gardeners. The main goal of rejuvenation pruning is height reduction, and in many cases, plants may be reduced in height by 75 to 90 percent. You will be removing all old wood, and the plant will begin producing new juvenile stems and new foliage shortly after pruning.
When pruning to rejuvenate azaleas, you may select a drastic one-step approach in the spring or a gradual two- or three-step method over a couple of growing seasons.
The “do it all at one time” approach works well for plants in good health and that have performed well in the past. You may cut all the stems and branches down to within a foot of the ground. This is usually completed at the end of the spring bloom cycle. It may be performed in early spring, also, before or during flowering if you live in an area with more stressful summer growing conditions for azaleas.
After pruning, there is no need to fertilize. Do not be concerned if no foliage is left. Much new growth will begin from the base within a month. Because there is so much emphasis from the plant on producing new growth, bud set in the late summer and into the fall for next spring’s flowers will be minimal. Return to fertilizing your Encore® Azaleas in the spring after typical flowering time in the year following pruning. You will see much-improved flowering on rejuvenated azaleas the second spring after major pruning. During re-growth, remove shoots at the point of origin that extend beyond the main plant canopy. This thinning will lead to improved size control and development of a more compact plant going forward.
A more gradual approach to re-invigorating your azaleas may also be used, distributing the pruning over several years. The best method is to cut back one-third to one-half of the stems to within a foot or so of the ground each spring for 2 to 3 years around flowering time, or at the end of the spring bloom season. This would result in a less dramatic change in appearance, but would still remove old wood and see new wood emerging. Cutting plants back one-third annually for 2 to 3 consecutive years would not result in the removal of old wood, but you would likely begin having some dieback in the canopy due to cutting plants back to the same point several times. When completing this more gradual rejuvenation pruning, fertilize as normal after you prune.
Major pruning is hard to conceive in many cases but can go a long way toward improving the long-term health and landscape performance of your Encore® Azaleas.