The hardiness zones for
Whether or not hydrangeas need protection depends on how cold the winter temperatures drop. If the air temperature doesn't go below 0 degrees (zone 7) there is no need for winter protection. In colder climates, wrap or completely cover marginally hardy hydrangeas.
Luckily, hydrangeas can tolerate some cold and are frost resistant due to their origins in Asia. But beware of severe (night) frost. Hydrangeas can survive the frost, but the buds can be damaged.
Potted Hydrangeas – Winter Protection
The best hydrangea winter protection for potted plants is to bring them inside prior to the first frost. If they are too cumbersome to move, they can remain outside and be protected by covering the entire pot and plant.
5. Bring potted hydrangeas inside. Potted hydrangeas overwinter best in a garage or basement where the temperature stays cool but doesn't freeze. The plants will go dormant, but you'll still need to water the pots occasionally, about once a month, to keep the roots moist, until spring.
You could try planting the hydrangea outdoors if weather allows, but it's important to remember that most indoor/gift hydrangeas were not developed with outdoor performance in mind. A large number of them are not very cold tolerant and will die in winter in areas colder than USDA zone 7 or 8.
Hydrangeas grown in the ground or in containers require 3 basic things; well-drained soil, the proper amount of sunlight and lots of moisture. Growing hydrangeas in pots is a great option for people who are limited in space, or would like to create a beautiful new look in their garden.
The size of your container matters, since the plant's roots will need room to grow into during their stay. We've found that pots measuring at least 16-24” wide and deep will often accommodate a good-sized hydrangea nicely for a few years.
The winter preparation for hydrangeas I see most often is a DIY version made with chicken wire and a few stakes. You build a cage larger than your plant and then stuff the opening with leaves, straw, pine needles, etc. making sure you get the insulating materials down and around the bare stems.
Some gardeners choose to protect their plants with horticultural fleece during the winter and Morris said should only be done in a few month's time: “If your hydrangea is in full growth in the Spring and a frost is forecast – you could cover the plant overnight with some horticultural fleece to minimise the damage.”
Hydrangeas don't look very nice in the winter. And they look even worse in the Spring! The old branches look dead at the end of winter (even though they're almost always just dormant); and they are unattractive for a while.
Put your container in a sheltered, full to part sun location (morning sun is best). Water a few times a week, or daily if needed. Fertilize once a year, in early spring. Cut hydrangeas that bloom on new wood down to one to two feet tall in the late fall.
Hydrangeas grow well in gardens, but can also grow in pots. They need well draining soil that has a slightly acidic pH. If these are not the conditions in your garden, I urge you to try planting a hydrangea in a container.
When you deadhead hydrangeas, you aren't harming the plants at all. Removing the spent blooms triggers flowering shrubs to stop producing seeds and instead put their energy toward root and foliage development. This makes plants stronger and healthier, so by deadheading, you'll be doing your hydrangeas a favor.
If you purchase the annuals small and make your own pots in early Spring, you can save money but you still are left with dead plants at the end of the season. Hydrangea plants are considered a perennial which will grow back year after year if care for properly.
If you don't prune hydrangeas then they can eventually resemble a tangled mass of woody stems, and the flowers will become smaller and less showy.
Hydrangea macrophylla, big leaf hydrangea
These plants produce buds in late summer to early fall (August-September) that will form next year's flowers. So prune these shrubs after they finish blooming before August (again, make a heading cut).
Hydrangeas that bloom on new wood require pruning in late winter or early spring. Prune to shape, cutting back to about two feet. The pruning promotes new, sturdy growth, which provides the blooms next season.
First, decide where you'll put the hydrangeas.
Many hydrangeas like morning sun and afternoon shade, so this also makes it easier to give them the growing conditions they prefer. You can also move them around to decorate a patio or other space for a party or special occasion.
While hydrangeas can grow successfully in a large container for several years, it's not permanent. If your plant becomes challenging to keep adequately watered, appears stunted, has small leaves, or the flowers are small or diminished, it's time to move on.
Hydrangeas will grow in either multipurpose or ericaceous compost but if you want them to turn blue, it is best to pot them in ericaceous compost.
When growing hydrangea as a houseplant, a period of dormancy during fall and winter is recommended. Move the plant into an unheated room with temperatures around 45 degrees F. (7 C.). The potting mix should be kept on the dry side, but water lightly as needed to prevent the plant from wilting.