Trim a shrub at the wrong time and it costs you a year of flowers or a winter of dieback. Here is the timing that works in the Treasure Valley.
Late winter to early spring (February to April)
This is the main pruning window for most shrubs. They're dormant, you can see their structure, and they'll push new growth right after.
Good now:
- Summer-flowering shrubs — spirea, potentilla, butterfly bush, hydrangea paniculata. They bloom on new growth, so cutting now doesn't cost you flowers.
- Overgrown shrubs that need a hard cutback. Most broadleaf shrubs recover well when cut back hard before spring growth.
- Ornamental grasses — cut them down to a few inches before the new green blades come up.
Right after blooming (May to June)
Spring-flowering shrubs — lilac, forsythia, flowering quince — set next year's buds soon after they finish flowering. Trim them within a few weeks of the blooms fading. If you trim them in fall or winter, you cut off next spring's flowers.
Through the summer
Formal hedges and sheared shapes — boxwood, privet, euonymus, globe spruce — look best with light trims through the growing season, typically every four to six weeks. Little and often keeps the line crisp and the inside full.
Stop by early September
Heavy trimming after early September triggers soft new growth that doesn't have time to harden off before the first freeze. That growth dies back over winter, and the shrub starts spring with brown tips.
Light tidying is fine later, but save anything major for late winter.
Shrubs that don't come back
Junipers, arborvitae and many spruce don't regrow from bare wood. Cut back past the green and that spot stays bare. If one of these has outgrown its space, it's usually better replaced than cut hard.
Need the hedges kept tight all season? See our shrub and hedge trimming, or price your yard.