Annual pruning is the key to coaxing a peegee hydrangea into a small tree that bears prolific flowers. Here, it is combined with lower-growing perennials.
Heading — To head a small branch or twig back to a bud, cut 1/4 in. above the bud and angle the cut at about 45 degrees, tilted in the direction the bud is pointing. A new branch will grow from the bud in the same direction. Use bypass pruning shears with a hook and blade to make the closest, most precise cuts on branches up to 3/4 in. dia.
Rejuvenating — It's possible to restore a neglected, overgrown shrub by cutting all the branches 4 to 8 in. above the ground. Use a pruning saw, which cuts on the pull stroke, on branches larger than 1 1/2 in. dia. The tapered end helps you work the saw into tight spaces, and the curve forces the wood into the teeth, which makes cutting easier and faster.
Thinning — Selectively cutting the oldest branches to the ground opens the center of the shrub to light and promotes new growth. Young, vigorous wood produces the most flowers.
These photographs show a dormant shrub before and after pruning. You can also thin by cutting a branch back to a side branch.
Use loppers on stems up to 1 1/2 in. dia. Their long handles increase leverage and help you reach into densely branched shrubs.
Summersweet (Clethra alnifolia) grows strongly upright with many slender stems that slowly form broad clumps. Prune only to head back any wayward stems, and periodically remove the oldest stems.
Beautyberry (Callicarpa japonica) requires annual pruning to control size and blooms, and to encourage fruit. It's best to rejuvenate annually by cutting all stems to a few inches above the ground. Another option is to cut one-third of oldest branches to the ground each year.
Peegee hydrangea (Hydrangea paniculata) can be a multistemmed shrub or trained as a tree by gradually pruning to a single stem. The canopy of the tree may need occasional thinning. On shrubs, cut one-third of the growth to the ground yearly. Rejuvenate by cutting all stems a few inches above the ground.
Common butterfly bush (Buddleia davidii) responds very well to heavy annual pruning by producing fewer, but larger, blooms. Cut back one-third of the oldest stems or prune all stems to within 8 in. of the ground, especially if winter dieback occurs. Common butterfly bush (Buddleia davidii) responds very well to heavy annual pruning by producing fewer, but larger, blooms. Cut back one-third of the oldest stems or prune all stems to within 8 in. of the ground, especially if winter dieback occurs.
Beauty bush (Kolkwitzia) should be pruned minimally each year, just enough to ensure strong new growth. Cut a few of the oldest stems to the ground. Take care not to injure new shoots emerging from the ground.
Lilacs (Syringa vulgaris) maintain a full, balanced form when a few of the oldest stems are pruned above ground level each year. Also remove suckers and narrow, weak shoots at the base of the plant. Prune spent blooms to encourage profuse flowering.
Forsythia becomes a tangled mess unless pruned each year.
To maintain its naturally graceful, arching form, cut one-third of the oldest stems on established plants to the ground. You can rejuvenate an overgrown shrub by cutting all of it stems several inches above the ground.
Japanese kerria (Kerria japonica) thrives with annual pruning. Cut most of the stems that have blossomed back to the ground. Cut a few low on the stem where new growth is sprouting. They will fill out the base of the shrub.
