Before you pick up your pruning shears to trim the hydrangeas, you need to know what type of hydrangea is growing in your yard, so you don't cut off the buds for new flowers. Most hydrangeas are multi-stemmed shrubs, but the Pee Gee hydrangea is grown as a shrub or shaped into a tree form.
Pee Gee hydrangeas have large, cone-shaped flower spikes covered in white flowers that turn pink, then brown in the fall. The oakleaf also has a cone-shaped flower spike, and oak-like leaves. Hills-of-snow hydrangeas have large, round balls of white flowers, while bigleaf or florist hydrangea, has balls of blue or pink flowers depending on the soil pH.
Properly pruned and trimmed hydrangeas reward you with colourful blooms year after year.
Trim dead or overly long stems in the summer on a climbing hydrangea (Hydrangea anomala petiolaris) once the vine is established in the landscape and climbing the structure you've trained it to climb.
Remove dead stems and shoots, called suckers, growing at the base of a bigleaf hydrangea, also called florist hydrangea (H. macrophylla), after the shrub stops blooming. Prune up to half of the old stems and any weak stems back to the ground. Delay pruning until the buds on the stems begin to swell if they were left unprotected over the winter. Cut off all the damaged, weak stems entirely or just below the injured portion of the stem if healthy flower buds are present on the stem.
Prune shoots, called suckers, growing at the base of Pee Gee hydrangea (H. paniculata grandiflora) in late winter or early spring. Also remove about half of the old or dead stems.Thin branches to increase air circulation and cut off spent flowers.
Trim broken, crossed, diseased or dead stems off the oakleaf hydrangea (H. quercifolia) in early spring after it has finished flowering. Prune stems damaged by cold back to the healthy portion, and remove the whole stem at the base if there are no healthy sections of stems left.
Cut all the stems of hills-of-snow hydrangea (H. arborescens) in late winter or early spring to between 6 and 12 inches long, if it was killed back to the ground. Cut off old, weak stems and trim the remaining healthy stems to a length of 1 to 3 feet, if it survived the winter.
Clean your pruning tools after you cut diseased branches. Don't prune bigleaf hydrangea after September.