Grow Huge Limelight and Annabelle Hydrangea Blooms With This Simple Pruning Hack

Shhh! We’re going to let you into a secret… there’s a simple hydrangea pruning hack that will bring the biggest blooms to your backyard. And we do mean big! This easy-do trick to prune hydrangea will give you mega monster-sized flowers on all panicle hydrangeas (Hydrangea paniculata) and smooth hydrangeas (Hydrangea arborescens), so if you’ve got a Hydrangea ‘Annabelle’ or Hydrangea ‘Limelight’ in your garden, you’re in luck!

Both panicle and smooth hydrangeas flower on new wood. This simply means that blooms form on fresh stems that grow in spring – which is why you can manipulate the size of the flowers so easily. These hydrangeas should be pruned in late winter or early spring, depending on your USDA zone, after your last frost date. Not sure what type of hydrangea you have and if now’s the right time to prune it? Do this vital check to make sure your hydrangea is a new-wood bloomer, and you can be confident you know the exact right time to prune.

Ready for blooms as big as a basketball? Let’s get down to business!

How to Get Bigger Hydrangea Flowers

Here comes the science bit! Imagine your hydrangea shrub has a finite amount of energy to grow its flowers. It could use that energy to create lots of smaller blooms, or fewer larger blooms. And that’s the first thing you need to know: if you channel the shrub's energy into huge flowers, you’ll get less of them – but we promise the overall effect is just as impactful, if not more so.

To force your shrub into directing all of its energy into fewer flowers, all you’re going to do is prune it hard, to concentrate its growing power. So, simply cut all the stems to around 8–10 inches from the ground. Make angled cuts, just above a pair of strong-looking buds. Now don’t panic! This looks brutal, and you’ll be left with a small skeleton of stems, but your hydrangea will be absolutely fine.

From this compact framework, huge blooms will grow on long stems. As well as looking fabulous in your garden, these showstopper blooms make superb cut flowers, and just one super-sized stem in a vase makes an all-eyes-on-me arrangement.

What do I Need to Know About Pruning This Way?

This is a drastic form of pruning, so it’s important that your hydrangea has a strong root system to support it. If your shrub is mature and already flowering well, and has been growing in your garden for at least two years, go ahead. If not, it's best to wait until your plant is more established.

It’s also vital that you use sharp hand pruners to make clean cuts that are easy for the shrub to heal. Ratchet hand pruners, also known as anvil shears, such as this pair from Amazon, have a geared mechanism that make it easier to cut through tough woody stems such as hydrangea. This assistive action is a real boon, slicing cleanly with less effort from you, even if you have small or arthritic hands. Regular bypass pruning shears will get the job done too, but do give them a sharpen first using a sharpening tool such as this nifty garden sharpener from Amazon.

Because you’re maximising flower size, you may need to support the top-heavy stems. A bird-cage support such as this one from Amazon works well for a smaller shrub, but you’ll need sturdy half-round stakes such as these from Lowes for a larger plant.

You’re also compromising the shape of the shrub a little, so rather than an evenly rounded bush, you’ll get long stems growing from a smaller mound.

If you're a beginner gardener and all this sounds a little scary, there’s a half-way house which gives biggish blooms and a more natural shape to your shrub. Just trim all the stems to around 18 inches to two feet, or remove a third of the growth, whichever leaves the shorter stems. If your hydrangea is very large, old or hasn’t been pruned for a few years, it’s also best to work up to the drastic hard-prune method by gradually reducing stem length over a few years.

How to Feed & Water Hydrangeas for Bigger Blooms

After pruning, you can also feed and water your hydrangeas purposely for bigger flowers. Hydrangeas appreciate consistent moisture, so water two or three times a week during dry spells. Make sure you water the soil around the plant base, rather than the leaves, and keep moisture in with an organic mulch such as these coconut husk chips from Amazon.

You can treat your shrub to a feed to energise it for strong growth, too. Too much nitrogen, though, and your hydrangea will prioritize leaf and stem growth over flowers, so don’t overdo it – if your soil is good, you probably don’t need to fertilize. On poorer soil, a balanced slow-release feed with an NPK ratio of 10-10-10, which supplies equal parts of nitrogen (N), phosphorous (P) and potassium (K), such as this all-purpose fertilizer from Amazon, will promote good hydrangea health. Apply after pruning in early spring, sprinkling around the shrub’s dripline (the ground beneath the outermost edge of its stems) and watering in well.

To maximise flower size, you can make a second application of a continuous-release bloom-promoting feed such as this one from Amazon in May. But use it very sparingly: too much and stems won’t be strong enough to hold up your maxi blooms.

Which Hydrangeas Can I Prune This Way?

You can use this method for all smooth hydrangeas. Many Hydrangea arborescens cultivars have been bred to produce huge blooms in the first place, so this pruning method will give you oversized flowers that will stop your neighbors in their tracks! Varieties include ‘Annabelle’ and the ‘Incrediball’, ‘Invincibelle’ and ‘Candybelle’ series.

This pruning method also works brilliantly well for panicle hydrangeas (Hydrangea paniculata). Their generous cone-shaped flowers often shift in color – sometimes quite dramatically – and bigger blooms make the most of this ever-changing summer display. Popular varieties include 'Limelight', 'Fire Light', ‘Pinky Winky’, ‘Vanilla Strawberry’, ‘Bobo’, ‘Skyfall’ and ‘Phantom’.