Good pruning keeps plants healthy, safe and blooming. Bad pruning can ruin a plant's shape for years. The key question is always when the plant sets its flower buds.
Spring-flowering shrubs: prune right after bloom
Shrubs that flower in spring, such as forsythia, lilac, azalea, rhododendron and bigleaf hydrangea, form next year's buds during the summer. Prune them within a few weeks after they finish blooming. Prune in fall or winter and you remove next spring's flowers.
Summer-flowering shrubs: prune in late winter
Plants that bloom on new growth, such as panicle and smooth hydrangeas, roses, butterfly-friendly salvias and crape myrtles, can be pruned in late winter or early spring before growth starts.
Trees
- Prune most trees in late winter when they're dormant and their structure is easy to see.
- Remove dead, damaged and crossing branches first.
- Never remove more than about a quarter of the canopy in a year.
- Cut just outside the branch collar, the slightly swollen area where a branch meets the trunk. Don't leave stubs or cut flush.
- For heavy limbs, use the three-cut method: an undercut, a top cut farther out to drop the weight, then a final cut at the collar.
Oaks and oak wilt
Oak wilt is a deadly fungal disease spread by beetles to fresh wounds. In areas where it occurs, including Texas and much of the Midwest, avoid pruning oaks in spring and early summer. In Texas, that means February through June. If you must cut then, paint the wound immediately.
Don't top trees
Topping, cutting large branches back to stubs, causes weak, fast regrowth and decay. The same goes for chopping crape myrtles to knobs each winter. Instead, choose a variety that fits the space and thin selectively.
Tools
Keep bypass pruners, loppers and a pruning saw sharp and clean. Sharp tools make clean cuts that heal faster. Leave large or high tree work to a certified arborist.