Rejuvenation and renovation (or renewal) pruning are forms or techniques of hard pruning.  These extreme methods of pruning shrubs can restore vigor to old, neglected, overgrown or misshapen shrubs.  These techniques involve cutting some shrubs to the ground or leaving only six to 12 inches of stubs.  While drastic, if done properly, the result is like replacing old shrubs with new ones.

Renovation or renewal pruning:  removal of old stems or canes over a period of three years with 1/3 of the oldest stems removed each year.  It is best done during the dormant season, right before new growth begins in the spring.  This results in a more vigorous shrub and, in the case of flowering ornamentals, better flowering.

• In early spring, remove 1/3 of the stems, cutting them all the way to the ground or main trunk.  Cut side branches back by 1/3.*
• In the second year, cut ½ of the remaining old wood, and
• In the third year, remove all remaining old wood.
• As you thin the shrub and the sun begins to penetrate to the center, new growth replaces the branches you have removed.  Most of our shrubs respond well to this method.

Rejuvenation pruning:  removal of all the stems or canes to ground level or up to 12 inches at one time and   allowing the shrub to regrow. In mid-summer, about ½ of stems should be removed and the remaining ones cut back to different heights. The advantage of this type of pruning is that the shrub recovers quickly.  The disadvantages of this type of pruning are that not all shrubs tolerate drastic cutting, and, until the plant regrows, you are left with an unsightly stub.

Recommended shrubs for rejuvenation pruning:  Leucophyllum, xylosma, oleander, hopbush, creosote, brittle bush, lantana, autumn sage, Mexican honeysuckle, and red bird of paradise.    

These methods are not appropriate for all shrubs. They work best with shrubs that consist of several stems arising directly from the ground. Shrubs with tree-like growth consisting of one main stem with several side branches are difficult to renew by this method.  Cassias, arborvitae, junipers and rosemary do not respond well and may die. A third, less drastic option is to prune all the stems or canes to unequal heights in one season.  Pruning by shearing will not correct the issues with old shrubs.