Americas most beloved shrubs.
Do hydrangeas like sun or shade?
Hydrangeas can be a little tricky to place! Some hydrangea varieties enjoy full sun while others enjoy a more shady location. Not all hydrangeas flourish in heavy afternoon sun, but panicle and climbing hydrangeas can handle it. Panicle hydrangeas really thrive in a full-sun environment. Macrophylla and serrata won't just wilt, they will burn up in full sun in hotter climates -- so, provide those hydrangeas with afternoon shade. Oakleaf can take full sun, but, in warmer climates, they also require some afternoon shade. Hydrangeas are a varied bunch: check the recommendations on your specific plants.
Do hydrangeas come back every year?
Hydrangeas are perennial plants, meaning they'll rebloom every year with the right care! You'll want to place your hydrangeas in a well-drained, partly sunny location to provide them the best chance for a long and happy life. These plants need lots of water, especially for the first year or two after planting. They can also make use of a light fertilizing twice per year: just as buds start to push new growth, and again in the summer. Hydrangeas should not be fertilized after mid-August. This allows all new growth to harden off before cooler temperatures set in. In the fall, a little winterizing will help them bounce back faster and better than before.
Before the first frost, cover the roots of your hydrangea plants to a depth of at least 18 inches with bark mulch, leaves, pine needles, or straw in the fall. With macrophylla and serrata varieties, you can actually cover a portion of the canes, as well. This insulation will help insure blooms next year by protecting the flower buds that have formed over the summer. Be sure to carefully pull back the mulch around the canes in the spring.
Deer tend to eat hydrangeas, especially in the winter. Deer will browse all hydrangea species, and, depending on other food sources available, they can cause quite a bit of damage. Oakleaf and arborescens hydrangea are particularly prone to deer browsing. So it's best to wrap the accessible parts of the hydrangea with a deer cage or wire. If that doesn't deter your deer, try a commercial deer repellent.
Do you cut back a hydrangea?
The pruning schedule depends upon the variety of hydrangea! Some hydrangeas, like oakleaf, bigleaf, and climbing hydrangeas, should be pruned immediately after flowering. Panicle and smooth hydrangeas can be pruned before spring.
For varieties that should be pruned immediately after flowering, make sure to prune before autumn -- flower buds actually form in the late summer and flower the following season. Any wood that died over the winter should be pruned away in spring: once the plant has fully flushed out, check to make sure you don't see new growth on the cane before cutting. On the branches that you aren't trimming back, leave the flowers -- you do not need to deadhead a hydrangea. These plants bloom on old wood, not new growth, so don't prune the wood excessively. Fantastic new breeding has introduced cultivars of macrophylla and serrata that do bloom on new wood, but the general rule for these hydrangeas is still: prune sparingly.
For panicle and smooth hydrangeas, you should prune in late winter, when the plant is dormant and before new flower buds have formed. You can prune to remove old wood, and crossed branches, as well as to shape the plant. Panicle and smooth hydrangea flowers bloom on "new wood."
What happens if you don't prune hydrangeas? You can get smaller blooms if you leave your plants unpruned, but it won't hurt the plant at all not to prune it. Most hydrangeas are happy to live unpruned and will still return every year.
Are hydrangeas deer resistant?
Hydrangeas are not deer resistant -- they aren't favorites of animals, but nonetheless, if conditions are sparse enough, deer will certainly resort to eating your hydrangeas. That typically happens in the winter.
Mophead, serrata, climbing and oakleaf hydrangeas bloom on old wood. Many other varieties have flowers that bloom on new wood, so wintertime damage might heal before the hydrangeas bloom. But, you don't want deer to consider your yard a buffet. They're creatures of habit, and often return to landscapes that have proven to provide easy meals. For short hydrangeas, we recommend using a wire cage in the winter. For taller hydrangeas, try deer repellant on the reachable branches.
Do hydrangeas change colors?
Some hydrangeas -- most macrophylla and serratas -- do change colors! In some varieties of these pink-to-blue hydrangeas, like Tellers Blue or Twist n Shout hydrangeas, the soil pH will affect the color of the flowers. These flowers become more blue in highly acidic soils, and lilac to pink in slightly acidic to alkaline soils.
To make your hydrangea flowers more pink, you'll need to raise the soil pH, making the soil more alkaline and less acidic. Try adding lime to the soil will make the flowers appear more pink. Dolomitic limestone will also add magnesium to the soil. Wood ash will also raise soil pH, but should be applied very lightly: too much can burn your hydrangea's foliage.
Lowered soil pH is often associated with hydrangeas of a bluer hue, but low pH won't make your hydrangeas blue on its own. Aluminium is the key to turning hydrangeas from pink to blue, and an acidifier without aluminum in it may not achieve the same effect. Aluminum availability in the soil is pretty common, but not universal, so look for amendments that include aluminum. In overly alkaline soils the aluminum ions are locked up with other elements, and don't flow to your plant. Lowering the pH allows those aluminum ions to break free and be taken up by the plant, producing the blue color.
Click here to read more on caring for your hydrangeas and tips for success.