Why Isn't My Hydrangea
BLOOMING?
Let’s Dance ¡Arriba!™ Reblooming Hydrangea
Big leaf hydrangeas produce some of the best-loved summer flowers: big, blousy orbs of pink, purple, or blue. Everyone, it seems, has one, but not everyone has found equal success in getting a yard full of fabulous flowers. This is why the number one question we are asked every year is, “Why isn’t my hydrangea blooming?” It’s a pretty easy question to answer yourself, once you have some basic knowledge of the one characteristic that makes these beautiful bushes a little bit different than the others: they bloom on old wood. Let’s take a closer look at what that means.
Bigleaf Hydrangeas Bloom on Old Wood
Shrubs that bloom on old wood create their flower buds for the following year shortly after they finish blooming (or should have bloomed, if you didn’t get any flowers) during the current one. In other words, the flowers are created on wood that is at least one year old, as opposed to developing in spring, once the new growth emerges.
Bigleaf hydrangeas are certainly not the only flowering shrubs to bloom on old wood. Several other popular plants, like forsythia, quince, lilac, and weigela also bloom on old wood. However, unlike those spring bloomers, big leaf hydrangeas bloom in mid-summer. This means that the window where they do not have flower buds for either the current or following year is not only smaller than for other old wood-blooming shrubs – it also occurs much, much later in the season.
In practical terms, this has a major impact on plant care, especially pruning. The normal pruning advice for shrubs that flower on old wood is that if you wish to prune, you should do so immediately after they finish blooming. For lilacs and the like, that leaves nearly six months of recovery before winter comes. However, for big leaf hydrangeas, that leaves only a month or so, which isn’t enough time for them to recover from the pruning and create next year’s flower buds before the days get short, the nights get cold, and the plant grows dormant.
Having flower buds already on the plant through fall, winter, and spring also means that they have to survive a long period without getting damaged by winter weather, or by animals, like deer, rabbits, and pets.
Ultimately, it’s the combination of blooming on old wood and blooming so late in the season that cause the frustration with this plant. Next, let’s take a closer look at the common problems that prevent blooming and how to resolve them.
Reasons Why Your Hydrangea Might Not Be Blooming
These are the four most common explanations for why big-leaf hydrangeas may not bloom.
How to recognize it:
Did you, or a well-intentioned family member, friend, or landscaper cut your big leaf hydrangea back? This is by far the most common reason a big leaf hydrangea won't bloom.
What to do about it:
This one is easy: just don't prune or cut back your big leaf hydrangea! There is no time of the year when they can be safely pruned without removing flower buds for the current year or the following. We recommend that you avoid pruning big leaf hydrangeas entirely.
If your plant is too large for its space and you need to cut it back, you can go ahead and do that in spring with the knowledge that your plant will have few to no flowers that season. It won't harm the plant at all, it just removes the blooms. However, it might be better to remove that plant and replace it with a newer, more compact variety that's a better fit for the space so you don't need to go without blooms.
How to recognize it:
Though big leaf hydrangea plants can survive winter in places as cold as USDA zone 5 (and in some cases, USDA zone 4), their flower buds, which spend all winter deep within the dormant buds, are not as cold tolerant as the plant themselves. As such, cold winter weather often causes the embryonic flower buds to freeze, killing them and any chance of blooming.
You'll know if winter damage is the reason your plant isn't blooming if, in spring, large portions of the stems show no signs of new growth. Usually, the bottom third or half has buds emerging, and the upper third or half stays brown. This is most common in zones 4-6.
What to do about it:
If you are seeing winter damage every year, that indicates the site is not favorable for big leaf hydrangeas. Try transplanting it in early spring to a more protected spot, such as on the east side of your home or another spot where it will be sheltered from the worst of the winter weather.
How to recognize it:
If your hydrangeas made it through winter without any cold damage, great! But you should still keep an eye on the weather through spring, as one of the most common but least-addressed reasons a big leaf hydrangea may not flower actually happens at this time of year.
As the days start to get longer and temperatures warmer in spring, the buds of all sorts of plants begin to unfurl. As the buds on big leaf hydrangeas begin to unfurl, though, they leave that tiny flower bud the plant set last summer increasingly susceptible to damage from any pesky mid-late spring frosts and freezes. If such cold temperatures contact the plant, the tender bud dies, and with it, the potential for flowering. This type of weather damage isn't just limited to cold climates - it can occur anywhere spring frosts and freezes are possible.
What to do about it:
Fortunately, this issue is easy to manage: just keep a close eye on the weather report in spring, especially after you've noticed green buds showing up on the plant. If a frost or freeze is predicted, cover the plants with an old sheet, towel, or blanket for the night. This prevents the cold, frosty air from directly contacting the delicate leaf tissue, preserving the flower bud. The covering can be removed the next morning when the danger of frost or freezing temperatures has passed. However, this will need to be repeated as weather dictates until the danger of frost has passed.
How to recognize it:
Deer browse all hydrangeas, and are especially fond of the flower buds. They are remarkably adept at nipping out just the growing point containing the flower bud, leaving little evidence that they were even there at all.
Big leaf hydrangeas are not their preferred type - that dubious honor goes to smooth and panicle hydrangeas - but deer damage is still very much worth considering if you have a hydrangea that's not blooming. They may also browse the plants when they are actively flowering, so if you come out to find your plants with fewer flowers one day, deer could be the culprit.
What to do about it:
You'll need to employ some level of protection to prevent the deer from feeding on your plants. A physical barrier, like a fence or netting, is the most permanent solution, though often the most expensive. You can also use a repellent spray, like Plantskydd or Liquid Fence, though these will need to be reapplied frequently throughout the season, which can become a chore. You can experiment with some simpler methods, like hanging bars of soap in your plants, spreading dog or human hair around your plants, or deer repellent granules, but these are often too good to be true - especially if you have a very severe deer issue in your yard, with multiple animals visiting multiples times a week.
Disappointed with Your Hydrangea? Try These Instead
Let’s Dance Can Do hydrangea is a fantastic pick for anyone who has struggled to achieve hydrangea bliss – and even for those who have! Here’s why: it has the unique ability to set flower buds down the entire length of its stem, instead of just at the tip, like most conventional hydrangeas. That means that even if the weather does its worst, even if it gets pruned, there are still flower buds on the plant to enjoy in summer.
Let’s Dance Can Do hydrangea is also one of the top reblooming hydrangeas on the market, with new flower buds emerging even before the first wave of blooms has faded.
Need those big, beautiful mophead flowers in your life? Try Let’s Dance Arriba hydrangea. This special plant is a hybrid between the classic big-leaf hydrangea and its hardier cousin, mountain hydrangea. That builds better cold tolerance into the flower buds so they are less likely to get winter damage.
If the information under the “winter damage” section above sounds like what you’re seeing on your hydrangeas each spring, Let’s Dance Arriba would be the perfect replacement for your existing, under-performing varieties.
Tuff Stuff is a mountain hydrangea, also known as Hydrangea serrata. It’s a close relative to the more familiar big leaf hydrangeas, but instead of occurring on the mild coastline of Japan, it grows up in the chilly mountaintops. As such, it has naturally developed better bud hardiness over time, and that carries through even to selections like Tuff Stuff.
This beautiful lacecap hydrangea truly is tougher than the rest when it comes to withstanding winter weather and spring freezes. It’s also beautiful enough to grow for its own sake, even if you don’t have weather issues impairing your hydrangea bloom.
Have a different type of hydrangea that's not blooming? Use our flow chart to figure out why.
