Can You Trim a Rhododendron When it Has Unopened Buds?

Time Frame

• Gardeners usually withhold pruning rhododendrons until just after the flowering ends. This lets you enjoy the seasonal flowers and still have ample time for twig and leaf regrowth after trimming. If part of the rhododendron shrub creates a hazardous situation, such as a branch blocking a walkway, scraping a building facade, or shading out or choking a nearby plant, pruning in summer or fall may be warranted. It's best to prune in late winter or spring. However, trimming and removing buds only results in no flowers from that branch this year.

Results of Trimming

• Clipping back branch tips and removing buds to shape or reduce the size of the rhododendron encourages bushiness. The standard procedure involves using a sharp-bladed hand pruners and making a cut 1/4 to 1/2 inch above a lower branch junction or leaf cluster. Then, in spring and summer, the dormant buds under the cut sprout and become new twigs with leaves. By fall, these twig tips mature, become more woody in strength and don a flower bud.

Aftercare

• After trimming or pruning the rhododendron, it's important that the plant is not subjected to environmental stress such as drought or impoverished soil. To encourage the best regrowth after trimming, monitor the soil and supplement rainfall with irrigation to keep the soil evenly moist. Keep the soil acidic, too. Add organic mulch or granular fertilizer in spring to enrich the soil so shrub roots obtain nutrients to sustain healthy new growth across the summer.

Rejuvenation Insight

• Old, leggy rhododendron shrubs may be severely pruned back, to a skeletal structure 18 to 30 inches tall, in late winter to early spring. This harsh pruning causes renewed vigor and new leafy branches to regrow and within two to three years, a rounded, dense shrub develops. Pruning in late winter does remove branches with flower buds, but the greater advantage of uniform, healthy new growth supersedes the loss of a few flower buds from the old scraggly branches.