Pruning to Rejuventae Old or Overgrown Shrubs
Older shrubs often grow out of proportion with their surroundings, and may have large amounts of unproductive wood. Two techniques are used to restore old shrubs, provided they still have sufficient vigor and are growing in a favorable location.
Keep the following in mind with rejuvenation pruning:
- Select an appropriate species. Not all shrubs respond well to drastic pruning. When in doubt, ask your local professional nurseryman or arborist.
- Observe proper timing. The preferred time for renovative pruning is just before emergence of new growth(bud break) in early spring.
- Give extra care to heavily pruned shrubs. Fertilization, watering, and pest control will be critical factors
- Consider the shrub's new appearance. What will be the immediate impact on the landscape?
Complete Removal Technique
The first technique involves complete removal of the entire plant 6-10 inches above the ground. Use heavy lopping shears and a pruning saw. Remove half of the new canes that develop by mid- summer, and head back some of the remaining canes. When using a heading cut, be sure to prune to outward-pointing buds so that the inner portion does not become too dense. Note that this does not work with all shrubs; it is most effective for shrubs that are highly multi-stemmed and which tend to freely send shoots from the crown, or those which tend to sucker from the base. Some shrubs that tolerate extensive rejuvenation are: abelia, dogwood, honeysuckle, hydrangea, lilac, mallow, rose-of-Sharon, spirea, butterfly bush, Annabelle hydrangea, and St. John's wort (hypericum). If in doubt, find out first whether a particular shrub will tolerate this kind of pruning; a wrong decision here may leave you with an empty space where a shrub once thrived.
Staged Removal Technique
The second technique for shrub rejuvenation removes growth more gradually. The first year, remove one-third of the oldest, unproductive branches. The next year, take one-half of the old, lingering stems. Finally, in the third year, prune out the remainder of the old branches. New, productive stems should quickly replace the old wood. This method takes longer to complete, but the shrub stays more attractive throughout the rejuvenation period.
