By Carolyn Plank, Master Gardener
Ever wonder when is the best time to prune hydrangeas and clematis? In this article I’ll help clear up the pruning mystery for these beautiful blooming plants.
When to prune hydrangeas depends on when it blooms. If the hydrangea blooms in late summer on new growth, pruning should take place in late winter or early spring before the shrub begins active growth. Some of the hydrangeas in this category include Limelight, Burgundy Lace and classic snowball types.
Most other hydrangeas that bloom on old wood (growth from the previous year) should be pruned in summer after they’re done blooming. Pruning too soon increases the risk of cutting off dormant buds.
Oakleaf, Big Leaf, Nikko Blue and other pink and blue flowering hydrangeas bloom from the previous year’s buds. If you want to maintain their size or shape, prune in summer before August. Ever-blooming hydrangeas such as Endless Summer also bloom on old and new wood and should also be pruned the same way.
Clematis pruning made simple. There are three groups of clematis.
Group I is in the Red Category (red means stop) and blooms in early spring set on old wood from the previous year’s wood and doesn’t die back in winter. Pruning should be done sparingly. This category includes Pink Perfection, Spooneri and Pink Swing.
Group II is in the Yellow Category (yellow means go slow) and grows on old wood in late spring/early summer, and on new wood in late summer or fall. This group should be given a light trim in March before it begins blooming. Remove dead wood and cut back remaining stems to 6-8”. This category includes Horn of Plenty, Patricia Ann Fretwell and Beautiful Bride.
Group III is in the green category (green means go) and blooms on new wood in summer and dies off to the ground over winter. In March, prune all stems back to a strong set of buds 12” from the ground. This category includes Summer Snow, Prince William and Mississippi River.
Stems of live and dead wood look alike. The leafy growth from the bud indicates a live vine. Always prune from the top down. Work down each vine until you find a live bud or growth and then stop once you find it. You can cut off all of last season’s growth to the ground; however, this results in a shorter plant, a few less flowers, and will bloom a little later.
Happy pruning!! Below are a few great sites to visit for further information:
University of Maryland Extension – Guide to Pruning Hydrangeas | University of Maryland Extension (umd.edu)
Wayside Gardens – Tips for Pruning Clematis l Wayside Gardens
Spring Valley Nurseries – Clematis Pruning Guide | Easy Clematis Care | Spring Hill Nurseries (springhillnursery.com)