The ENDLESS SUMMER series of Hydrangeas is a collection of bigleaf Hydrangeas (Hydrangea macrophylla). Bigleaf Hydrangeas primarily bloom on last year’s growth, or “old wood.” For this reason, bigleaf Hydrangeas should never be pruned in late summer or fall. Pruning last year’s growth effectively removes the next season’s flower buds. Wait to prune until mid to late spring when you can assess winter damage, and only remove dead canes. Winter conditions determine how well your Hydrangeas will bloom. Extremely low and fluctuating temperatures as well as late frosts are very damaging. Plants that are killed to the ground rarely produce flower buds that season.
The ENDLESS SUMMER series is marketed as producing flowers on new wood. Although being touted as hardy to Zone 4, harsh winters often kill the flower buds of this series in New Hampshire. ENDLESS SUMMER THE ORIGINAL will often bloom on current season’s growth, but not consistently. After a severe winter, expect to see only a handful of flowers at the most.
Heavy snow cover can protect the buds of bigleaf Hydrangeas, but this is obviously hard to predict. Wrapping Hydrangeas can also sometimes be effective. Try wrapping the plant with burlap or chicken wire and filling in the enclosure with leaves. Wait to remove winter protection until all danger of frost has passed in the spring. Unfortunately, even these extra measures aren’t always effective. If you’ve tried wrapping your plants and you still aren’t getting blooms, consider relocating your plant to a more protected site in your garden, or try another cultivar such as ENDLESS SUMMER BLOOMSTRUCK or ENDLESS SUMMER TWIST-N-SHOUT that bloom on new wood more readily.
This was your Question of the Week. Got questions? The Ask UNH Extension Infoline offers practical help finding answers for your home, yard, and garden questions. Call toll free at 1-877-398-4769, Monday to Friday, 9 a.m. to 2 p.m., or e-mail us at answers@unh.edu.
Author(s)
