By Joyce Arleen Corson
Recently a friend asked me why her hydrangea didn’t bloom this year. Many situations may affect why a plant will not bloom. The name hydrangea comes from the Greek “hydra” meaning water, and “angeion” meaning vessel, in reference to the plants affinity for water and shape of the seed pods. Making sure your hydrangea receives plenty of water is important.
In discussing hydrangeas, most sources divide this genus into five major groups: Climbing Hydrangea, Smooth Hydrangea, Panicle Hydrangea, Oakleaf Hydrangea, and Bigleaf Hydrangea. Deadheading is the practice of removing blossoms after they fade.
Hydrangeas, native to Asia grow in hardiness zone 5 through 9 in United States. They grow from 3’ to 6’ tall, depending on the variety. You don’t need to prune them unless they have become unsightly or over- grown. The practice of removing spent flowers, called deadheading, is a separate chore, not a type of pruning.
You can remove spent blooms any time of year without harming flowering for the next year. If you cut blossoms, for flower arranging in August, cut them with short stems to avoid eliminating buds that will produce blooms the next year. One of my hydrangeas is a Bigleaf Hydrangea called ‘Endless Summer’. It will bloom on both new and old wood. It is also planted in a protected area near my house. Too much cold shouldn’t affect its ability to bloom.
Excessive nitrogen can be a problem for any flowering plant, not just hydrangeas. It promotes growth of leaves rather than flowers. If your hydrangea still won’t flower, “wait ’till next year”, just what you don’t want to hear.
My opinion is that given proper temperatures, sun exposure, and nutrients, a hydrangea that refuses to flower just needs time. That’s a hard point to swallow in our hectic society, but Mother Nature just may have some lessons to teach us if we take time to listen. Hydrangeas are generally considered to be an understory plant, thriving in partial shade. They do need some sun in order to flower well. Morning sun and afternoon shade is ideal.
Panicle hydrangeas (H. paniculata) and smooth hydrangea (H. arborescens) flower on new wood that grows in the spring. You can prune them to improve their looks, but you do not have to prune them at all if you don’t want to. If you prune an older plant it will grow longer stems, which are good for flower arrangements. If you want your hydrangea to bloom again, prune it after it flowers. If you prune it back in the winter, it will flower the following year. Panicle hydrangea cultivars include “Brussels Lace,” “Kyushu,” “Pee Gee,” “Pee Wee,” “Pink Diamond,” “Unique” and “White Moth.” Smooth hydrangea cultivars include “Annabelle,” “Hills of Snow” and “Samantha.”
Another group of hydrangeas flower on buds that formed during the previous growing season. If you prune these hydrangeas from late fall through early spring, you will eliminate flowers for the coming growing season. Prune about one-third of the older stems each year. If you want to prune them drastically, do it after they produce flowers. These species include the native oakleaf hydrangea (H. quercifolia) and the bigleaf or mophead hydrangeas (H. macrophylla var. macrophylla), lacecap hydrangeas (H. macrophylla var. normalis).
Climbing hydrangeas (H. anomala) produce flowers from side shoots. You ordinarily do not prune these hydrangeas, but you can prune the shoots back to the last healthy bud in the fall when blooming has stopped.
This Endless Summer hydrangea is growing with Eastern exposure. It doesn’t receive shade in summer until noon. Notice the blue flowers are in more shade than the pink in full morning sun.
Ben and Claire are by Annabelle Hydrangea. This shrub gets cut to the ground each season. Anna- belle has always flowered since moved here from a heritage garden. It is facing NE with only four hours of morning sun in summer and gets plenty of water from the sprinkler.
In other situations such as merciless weather, late frost or even hail, blossoms of flowers, shrubs and trees can be damaged .