When to Prune Flowering Shrubs: Spring Bloomers, Summer Bloomers and What to Leave
Quick answer
Prune spring-blooming shrubs right after they finish flowering, and summer bloomers in late winter or early spring. Skip routine pruning from mid-August to leaf fall. Dead, diseased, damaged or crossing branches can come out any time.
The right time to prune a flowering shrub depends on when it blooms and whether it flowers on last year’s stems or this year’s growth. Prune at the wrong time and you cut off next year’s flowers. This guide sums up the timing rules from university extension services and lists common shrubs.
Prune right after they finish flowering
Prune in late winter or early spring
Skip routine pruning
Dead, diseased, damaged or crossing branches
Old wood or new wood?
Spring-flowering shrubs bloom on one-year-old wood that grew the previous summer. Rutgers notes they “generally bloom before the end of June and should be pruned immediately after flowering.” Prune them before they bloom and you remove the flower buds that formed last year (Rutgers FS1221).
Summer-flowering shrubs bloom on new wood that grows in spring of the same year, so they “should be pruned in late winter or early spring” to push vigorous growth early in the summer (Rutgers FS1221).
When not to prune
Rutgers advises against pruning spring- or summer-flowering shrubs from after mid-August through leaf fall. Pruning stimulates new growth that may not harden off by winter, which can lead to cold damage. The exception is the “Four D’s”: dead, diseased, damaged or double-crossed limbs can be pruned out at any time. Don’t prune newly planted shrubs unless limbs are damaged; they need all their leaves to regrow roots (Rutgers FS1221).
For perennials, roses and subshrubs in fall, see our fall cutback guide.
When to prune common shrubs
Shrub-specific extension guidance comes first in this table. Where a general pruning chart puts the same shrub in a different group, the source column says so.
| Shrub | Blooms on | When to prune | Source |
|---|---|---|---|
| Common ninebark | Old wood | Just after bloom, “no later than mid-August” | NC State |
| Virginia sweetspire | Last year’s wood | After flowering | NC State; FS1221’s general chart lists sweetspire with summer bloomers |
| Arrowwood viburnum | Spring bloomer | After flowering | NC State; Rutgers FS1221 |
| Oakleaf hydrangea | Old wood | After flowering, no later than midsummer; it needs little pruning | UMD, Clemson |
| Dwarf and large fothergilla | Last year’s wood | Rarely needed; if you shape it, right after it flowers | Clemson |
| Smooth hydrangea | New wood | Late winter; it “can be pruned back close to the ground” without losing flowers | NC State; FS1221’s general chart lists it with spring bloomers |
| American beautyberry | New wood | Late winter, to about 1 foot high | NC State |
| Inkberry | Evergreen | If needed, “in early spring just before new growth begins” | NC State |
| Red-osier (red-twig) dogwood | Grown for red stems | Cut older stems in early spring for brighter red | NC State |
| Lilac, forsythia, weigela, mock orange, rhododendron and azalea | Spring bloomers (one-year-old wood) | Immediately after flowering | Rutgers FS1221 |
| Butterfly bush, rose of Sharon, bluebeard, chaste tree, summersweet | Summer bloomers (new wood) | Late winter or early spring, before growth begins | Rutgers FS1221 |
Profiles of the first nine shrubs, with zones, sun and soil, are in our low-maintenance shrubs guide. If you’re not sure which group a shrub is in, note when it flowers: spring bloomers are pruned right after flowering (Rutgers FS1221).
How much to cut: the one-third rule
Start with anything dead, diseased, damaged or crossing, then suckers at the base and water sprouts growing straight up through the plant, then older wood that no longer flowers. Rutgers suggests the “one-third rule”: each season, remove about one-third of the oldest wood at ground level and cut back about one-third of the younger canes by about a third of their height. That opens the plant to light and air and keeps it renewing itself (Rutgers FS1221).
Renewal and rejuvenation
Cutting one-third of the oldest stems to the ground is renewal pruning, and it can be done in spring or summer. Cutting all the stems to within six inches of the ground in early spring, before growth starts, is rejuvenation pruning. Rutgers recommends doing it no more than every three to five years, and lists multi-stemmed shrubs that handle it well, including forsythia, spirea, weigela, potentilla, hydrangea, red-twig dogwood and privet (Rutgers FS1221).
Making cuts, shearing and tool care
- Heading cuts shorten a branch back to a bud: cut 1/4 inch above the bud, sloping down and away at about 45 degrees. The bud’s direction sets the direction of new growth.
- Thinning cuts remove a whole branch where it starts, which opens the shrub without changing its natural form.
- Shearing is quick, but frequent shearing removes most flower buds and makes a thick outer shell that shades out the inside of the plant.
- No wound paint. Dressings don’t prevent decay or help healing. When cutting out diseased wood, cut into healthy wood and disinfect tools between cuts with rubbing alcohol.
All four points: Rutgers FS1221.
Frequently asked questions
Can I prune shrubs in fall?
Avoid it. Rutgers advises against pruning spring- or summer-flowering shrubs after mid-August through leaf fall, because pruning stimulates new growth that may not harden off before winter. Dead, diseased, damaged or crossing branches are the exception and can come out any time.
What happens if I prune a spring bloomer in early spring?
You cut off flowers. Spring-flowering shrubs set their buds the summer before, so pruning before they bloom removes those buds and reduces or eliminates flowering (Rutgers FS1221).
Should I seal pruning cuts?
No. Rutgers says not to use wound dressing or paint on pruning cuts: they do not prevent decay or aid healing.
Should I prune a shrub I just planted?
Only to remove damaged limbs. Newly planted shrubs need all the leaves they can get to regrow roots (Rutgers FS1221).
Sources & further reading
- Rutgers NJAES: Pruning Flowering Shrubs (FS1221)
- University of Maryland Extension: Pruning hydrangeas
- Clemson Cooperative Extension HGIC: Pruning hydrangeas
- Clemson Cooperative Extension HGIC: Fothergilla
- NC State Extension Gardener Plant Toolbox: plant profiles for ninebark, Virginia sweetspire, arrowwood viburnum, smooth hydrangea, American beautyberry, inkberry and red-osier dogwood
More guides
Pruning guides Fall cutback guide Low-maintenance shrubs All guides