Question: My hydrangeas have beautiful green leaves but they are not blooming. I had one lonely flower on one of my plants. My neighbors have the same complaint. Can you help me?
Answer: Failure to bloom is one of the most common problems with hydrangea. Six main things can contribute to why your hydrangea is not blooming.
Location: The first thing you need to do in determining why your hydrangea is not blooming is identify the species you have. Several species of hydrangea are commonly grown in New Jersey: Hydrangea macrophylla (bigleaf, hortensia or florists’ hydrangea), Hydrangea paniculata (panicle or Pee Gee hydrangea), Hydrangea arborescens (smooth or wild hydrangea), Hydrangea quercifolia (oakleaf hydrangea), Hydrangea anomala petiolaris or climbing hydrangea, and Hydrangea serrata (mountain hydrangea). All of these are hardy in our USDA Zones (6-7) but each has different cultural requirements. Since there are more than 23 different species and maybe as many as 75 to 80, it is important to choose varieties that are hardy in the zone you are located in to be sure they can survive our weather patterns. You can contact your local extension office to help you identify the type you have. Our helpline volunteers will ask you to send in a photo to help in identification.
Pruning: Once you know the species of hydrangea you are working with, you can determine the proper pruning method. Hydrangea are a very low maintenance plant. They really do not require a lot of pruning, but if you do prune it is imperative that you prune at the right time. Some hydrangea bloom on new growth, which means that they can be pruned through the winter and early spring and still be full of blooms that year. Others bloom on old wood, meaning last year’s growth, and pruning in winter and spring may remove all of the blooms for the current year. When you are placing them in your landscape, consider the full grown size which may reduce the need for pruning anything more than dead wood.
Light: Next, consider the location of your hydrangea. Light requirements are very important in all plants, and many species of hydrangea require four to six hours of sun, preferably in the morning, to thrive. Oakleaf hydrangea, however, grows well in shade.
Age: Keep in mind when you purchase and plant that some hydrangeas can take several years to mature and bloom. When you purchase from a nursery, choose plants that already have blooms to avoid the wait.
Winter damage: The fifth thing that may affect your blooms on hydrangea is winter damage. Even species that are considered hardy to our area may suffer damage from late spring frosts. One of the most common species grown in New Jersey is the bigleaf hydrangea, which is very susceptible to winter frost. There are some frost-resistant cultivars that are less likely to be damaged or drop blooms. Site the plants in a protected spot in the landscape or provide winter protection.
Animals: The last thing to consider if you hydrangeas are not blooming is unintended pruning from animals. Even when humans have held to pruning at the correct times for the species they are growing, deer and other wildlife may come in and prune them for you, causing them not to bloom.
For more information on hydrangeas you can contact your local extension office. Atlantic County residents can contact the Master Gardener Helpline at 609-625-0056. Cape May County residents can call 609-465-5115, ext. 3607.
Events: Atlantic County Master Gardeners will be available to answer gardening questions and take samples for plant identification or diagnoses throughout the county this fall. You can find us at the Hammonton Green Day Festival, Sept. 21. We will also be available at the following Atlantic County Library branches evenings from 5:30 to 8 p.m.: Egg Harbor City, Oct. 1 and Nov. 5; Hammonton, Oct. 2 and Nov. 6; Galloway Township, Oct. 3 and Nov. 7; Brigantine, Oct. 9 and Nov. 13; Mays Landing, Oct. 16 and Nov. 14; Ventnor, Oct. 16 and Nov. 14; Pleasantville, Oct. 21 and Nov. 18; Somers Point, Oct. 15 and Nov. 19; Egg Harbor Township, Oct. 16 and Nov. 20.
Do you have a gardening related question you would like answered here? Please forward your questions to Belinda Chester, Master Gardener Program Coordinator, Rutgers Cooperative Extension Office, 6260 Old Harding Highway, Mays Landing. You can also submit questions at Rutgers-atlantic.org/garden or email them to email@example.com; please include “garden question” in the subject line.