Preparing Your Hydrangeas for Winter
Longfellow’s Greenhouses | Nursery Department
(Photo courtesy of NetPS Plant Finder)
With the summer gardening season coming to a close and the chill of autumn in the air, it’s time to start thinking about putting your garden to bed for the winter. One of the most common questions we get this time of the year is how to prepare our hydrangeas for winter, and if we should be pruning them now or in the spring (or should be we pruning them at all?). The short answer is, it depends. Let’s dive into a little info about the different species of hydrangeas and why the species of hydrangea you are dealing with matters when it comes to pruning.
Pruning hydrangeas is very simple once you know what type of hydrangea is in your garden. Here at Longfellow’s Greenhouses, we typically carry 3 different species of hydrangeas;
We carry many different varieties within these different species categories. Head on over to our website and search through our online plant guide to determine which type of hydrangea you have growing in your garden.
Old wood vs new wood – Does your hydrangea form flowers on its old woody growth, on new growth, or both?
Old wood means that the buds are formed for next year’s blooms at the end of the current growing season. Hydrangeas that fall into this category are typically pruned after flowering in the late fall/early winter, or early spring to encourage new flower buds on old stems.
New wood means stems that have emerged during the current growing season that did not exist before this growing season began. Flower buds are formed on this new growth in the current growing season. Hydrangeas that fall into this category are typically pruned in late winter after a hard freeze, or in early spring before new growth emerges to encourage new stems.
If you get the timing wrong, don’t worry, hydrangeas are forgiving plants. You may go a season without blooms, but with proper timing you can expect flowers the following year.
So which species of hydrangeas fall into which categories?
Hydrangea Macrophylla – Bloom on old wood and new wood.
Macrophylla hydrangeas set flower buds on old growth at the end of the current growing season, and will also set flower buds on new growth next spring. For this reason, prune these hydrangeas in late summer or early fall to allow some re-growth and new flower buds to form before winter sets in. In addition to those flower buds that form before winter, more new ones will be produced next spring.
Hydrangea Paniculata – Bloom on new wood only
Paniculata hydrangeas set flower buds on the new growth that emerges on top of old woody growth each season. You might not need to prune paniculata hydrangeas every season. The only reason for pruning hydrangeas in this species is if they seem overgrown or floppy, and you are looking to tune them up.
Hydrangea Arborescens – Bloom on new wood only
Arborescens hydrangeas set huge flower buds on new growth each season. Old varieties such as ‘Annabelle’ can become floppy especially after heavy rains and/or strong winds. Arborescens hydrangeas will naturally die back to the ground at the end of each growing season, therefore you are safe to prune these back to the ground at the end of each growing season.
When pruning Macrophylla or Paniculata hydrangeas, never remove more than one-third of the total plant size each season. When pruning Arborescens hydrangeas, don’t be afraid to prune aggressively, pruning them back to the ground at the end of the growing season.
(Photo courtesy of Monrovia.com)
Hydrangea stems should be pruned at 45-degree angles right above a new bud. This new bud will be the location of new growth that will emerge next spring once temps warm enough to break the plant out of its winter dormancy.
Here are a few other tips to help your hydrangeas be as big, bright, and beautiful as you hope they will be next season…
- Give your hydrangeas a boost of natural nutrients late in the season by adding a couple inches of compost to your beds around your plants late in the fall. Applied in late fall, the compost will continue to break down over the winter and the nutrients stored up in the compost will be readily available for the plants in the spring. Do not fertilize your hydrangeas this time of the year with nitrogen-rich fertilizer as they should be starting to go into dormancy, and adding this kind of fertilizer can lead to additional new, weak, late season leafy growth which is unwanted this late in the season.
- After the ground has frozen, apply a deep layer of mulch around and against your hydrangeas (most importantly your Macrophylla hydrangeas). This mulch insulates the roots and crown of the plant especially during winters with little snow and very cold temperatures (deep snow actually acts as a good insulator, so winters with little snow are hard on the plants that would typically be buried under the insulating layer of snow). Don’t mulch too early as this can invite rodents to make their homes against your plant, and can also lead to rotting and disease if things haven’t frozen up yet.
- For Paniculata and Arborescens hydrangeas this winter protection alone should suffice. For Macrophylla hydrangeas, consider also wrapping the above ground portion of the plant in a couple layers of burlap or burying under some organic material such as leaves and bark mulch, as this will help to protect the more tender buds from the harsh mid-winter temps. Be sure to remove the burlap and deep mulch from the plants in the late winter/early spring before the plants start thinking about coming out of their winter slumber for a new season of growing and flowering!
- Don’t forget to still water your hydrangeas before the ground freezes up if the weather pattern is dry! Just because the plants foliage and flowers are fading doesn’t mean it no longer needs water for the rest of the season. If little to no rain falls for days on end, consider giving your hydrangeas a deep watering. Note that they will not use as much water as they did during the middle of the summer, so once you water them, you will probably be good to go without watering them again for close to a week or even more if temps are chilly and rain re-enters the forecast.
Following these late season care and pruning tips should help you achieve a very successful hydrangea season next year. There are still many other factors that can affect the flowering success of hydrangeas, so if you follow these tips and are struggling to have happy hydrangeas, give us a call or send us a message here at the greenhouses and we’d be glad to help you out!
Happy Fall, Longfellow’s Nursery!