Hello. You kindly just helped me with a pest problem and now I have a hydrangea question. We have 5 large Endless Summer Hydrangeas that are 10 years old. They were blooming when planted, bloomed the following summer, bloomed in 2017, but not in any other year. Each fall, the buds appear on the old wood, but every spring, they dry out. We wrap the plants in the winter, but to date, have not covered the tops. Can you advise on two things: How do we manage the unsightly branches with the dried out buds that stick out above the new growth? How do we encourage more consistent blooming? We have been fertilizing in early May only with 10-10-10. Picture of complete plant attached. I will send in another request with a close up of the dried out buds.
Thank you for contacting the Toronto Master Gardeners and for submitting two clarifying photos.
Endless Summer® hydrangeas bloom on the current year’s and previous year’s growth. In answer to your first question, especially now that we are in summer, you could cut off the brown stalks from last year’s growth. But before you do that, you need to determine if your plant’s stems are indeed completely dead. Scrape a fingernail or sharp knife into the bark of a stem you suspect as being dead. Start at the top. If you see some green then it means the branch is alive. Examine closely looking for any swelling buds which also indicate life. If you determine the whole stem is dead then cut it out completely. Dead stems will probably be brittle and dried out. If its only the top of a stem that is dead, remove the dead part by making a 45 degree angle cut about 1/4 inch above a bud. Only leave healthy wood and/or new growth from the base of the plant.
Several factors can impact blooming, including winter conditions, pruning practices, over-watering and over-fertilizing. These plants are not great feeders so there is no real need to fertilize. However, do make sure that the soil is kept moist during the growing season.
In areas where winter temperatures reach or go below freezing, there is a risk of flower bud loss, since buds form primarily in late summer and early fall of the previous year. For this reason, it is recommended that you do not prune or cut back the hydrangeas after August 1 and, if possible, leave fall blooms on the plants over winter. We did have a record-setting cold early spring, likely resulted in your hydrangeas having little to no flower buds this year. You might see some flowers yet on the Endless Summer® hydrangeas, as they may still produce blooms on this year’s growth.
Since your hydrangea plants have not bloomed for years, there may be something else that is not right for them. A struggling plant can be due to disease, pest, incorrect culture, or being ill suited to its site. Have you observed anything unusual about the plants aside from the lack of bloom? Hydrangeas can be susceptible to bud blight, bacterial wilt, leaf spots, mold, rust and powdery mildew. Pests to watch out for include aphids, mites, leaf-rollers and scale.
Here are a couple of sites you can look at for more information regarding pests and diseases of hydrangeas.
http://www.ladybug.uconn.edu/FactSheets/hydrangea-diseasesand-pests.php
https://www.canr.msu.edu/news/rose_chafers_a_punctual_and_pesky_insect
The best defense is to make sure your plants are healthy so that they can recover from attacks by pests. Although hydrangeas are easy to care for plants, they prefer full morning sun with afternoon shade and like to be well watered. If your soil is poor, add compost and if sandy, fertilize once a year in late winter or spring. Don’t over fertilize as you may end up with more leaves and fewer flowers.
Please take a look at this succinct plant profile to see if your plants are receiving the correct culture (e.g. amount of watering, level of fertilization, etc.) and if it is correctly sited (e.g. hours of sunlight, amount of drainage, etc.).
All being well your plant should grow back but most likely you will have to give up on blooms this year. For even more information on caring for hydrangea please check the following websites: