A question we, at GardenSmart, are most often asked is, “Why doesn’t my hydrangea bloom? I feed it. I water it. I prune it.” Ah ha! The last might be your answer. Our guest writer this week is Ryan McGrath, of Spring Meadow Nursery, Inc. home of Proven Winners ColorChoice shrubs.
You prize your hydrangeas for their beautiful flowers. You also want to make sure you prune them at the right time to encourage the stunning blooms every season. But, do you wonder whether or when to prune them?
“The first step is to determine the variety of your hydrangea,” said Tim Wood, new product manager at Proven Winners ColorChoice. “This is fairly easy to do. If your plant produces big pink or blue flowers, it is a Hydrangea macrophylla. If its flowers are round and white—or pink in the case of the new Invincibelle Spirit—the plant is a Hydrangea arborescens. Finally, if the plant has large, conical flowers, which are often white but may also be green or pink, you own a Hydrangea paniculata.”
If you have Hydrangea macrophylla, also known as Bigleaf Hydrangea, Wood says you can relax. This plant requires little more than a trimming and only immediately after flowering. You should never prune it in winter or spring, because it sets flower buds the year before and if you shear it back, then you will cut off all of summer’s flowers.
Newer reblooming varieties such as the Let’s Dance series from Proven Winners ColorChoice will also bloom on the current season’s growth, but you still want to leave the plant intact through spring so you can enjoy early summer flowers.
Hydrangea arborescens, also known as Smooth Hydrangea, is beloved for its adaptable nature and reliable blooms. You should prune it back in late winter or early spring. These hydrangeas bloom on “new wood”—the current season’s growth. Pruning them back at that time encourages new growth, which produces flowers. Spring pruning will also result in a fuller, stronger plant that’s less likely to flop under the weight of its abundant summer flowers. Cutting the stems back to one or two feet will leave a good framework to support the blooms.
Today, there are two new “Annabelle” Hydrangea arborescens with stronger stems, so they won’t flop after being established. Invincibelle Spirit Hydrangea is the very first pink-flowered
form of “Annabelle.” Invincibelle Spirit continues to produce new pink flowers right up until frost, providing a beautiful display across several seasons in your garden, from mid-summer to
fall. Incrediball Hydrangea has the biggest flowers and the strongest stems of any of the “Annabelle” hydrangeas. Incrediball produces incredibly large white blooms as big as a basketball.
Hydrangea paniculata, sometimes called Hardy Hydrangea, also blooms on new wood. You
should prune it back in late winter or early spring. You can cut it back to the ground or, if you
want slightly taller plants, cut it back to one to three feet. This is a great job for one of those
early spring days when everything is still dormant but it’s so beautiful and warm you need to be in the garden.
A new variety of Hydrangea paniculata won’t require as much pruning to keep it smaller. The new Little Lime Hydrangea boasts the same colors and benefits of the famous “Limelight” Hydrangea though only reaching three to five feet fully grown. At one-third the size of other hardy hydrangeas, it fits well into practically any landscape. Little Lime produces bright cone shaped lime-green flowers, later turning into pink, from mid-summer to frost.
Fortunately, even if you make a mistake and prune at the wrong time of year, these plants will forgive you. You may not have flowers for a season but, with proper timing, you’ll see them the following year. Just remember to start by correctly identifying which kind of hydrangea you have. With just a little work, you’ll get beautiful flowers from your hydrangeas year after year.