Pruning Rules of Thumb

Pruning can be confusing. Mostly because of a couple of questions: When is the right time to prune? How much do I cut off? While each plant can be a little different, there are some general guidelines to get you started.

Reasons for Pruning

Rejuvenate. Shrubs that have become leggy or have weak flower production can be helped a lot with a good pruning. This heavy pruning is best done in late winter or early spring.

Shape. This lighter pruning is just to direct things towards the desired look for your plants. You’ll only cut back up to 1/3 of the branch’s length. You can prune evergreens, hedges and deciduous shrubs like whenever you want.

Clean. Removing dead, damaged or diseased branches can and should be done at any time of year. Cutting off growth gone bad, or stray branches (like sucker shoots that surround the trunk) will help your plants stay healthy. This is the most basic pruning and the minimum that is needed.

Rules of Thumb for Pruning

  1. Stop! You don’t need to be pruning your shrubs all the time. Plenty of shrubs look fantastic when left to grow in their natural habit without pruning. If you like how it looks, leave it alone. However, if your plant’s size is growing out of control or it’s flowering less than it used to, pruning is a good choice.
  2. Prune Spring Flowering Shrubs AFTER Flowering. These plants produce their blooms a year in advance. So, cut them back if needed as soon as they’re done flowering. Pruning them in the fall or winter will cut off the buds.
  3. Prune Summer Flowering Shrubs in Fall or Winter. These plants produce their blooms on new growth. Pruning in late winter will encourage branching, new growth and more flowers.
  4. Hydrangeas. These are the one type of plant that generates most of the pruning questions. First, you need to know what type of hydrangea you have to know when to prune.
    • Bigleaf and Oakleaf Hydrangeas (H. macrophylla & H. quercifolia) bloom on previous year’s growth. You’ll know these by their big pink or blue flowers, or by their oak leaf shaped leaves. Prune them lightly to control the shape immediately after they bloom.
    • Smooth and Hardy Hydrangeas (H. arborescens & H. paniculata) bloom on new growth.. You’ll know these by the round and white blooms, or the large conical flowers. Prune them heavily in late winter or early spring.

The good news is that plants are forgiving. They’ll recover and bounce back from almost any pruning session.