Spring Hydrangea Help

May 16, 2022 | CLFornari | Hydrangeas

From planting to pruning, our customers have questions about hydrangeas. Here are tips for May maintenance and creating some landscape magic with new Hydrangea varieties.

What new varieties of Hydrangeas are available?

There are new and improved Hydrangeas that come to market every year. Here are a few Proven Winners varieties that are perfect for Cape Cod gardens.

If you have an area that’s in full sun, you should consider growing one of the Hydrangea paniculata varieties. Also called panicle hydrangeas, these plants do well in sun and flower on new growth, so pruning them in the fall or early spring won’t affect their flowering. Fire Light Tidbit will grow 2 to 3 feet tall and wide. As the flowers mature they turn a lovely pink color.

One of the newest kids on the block is Lime Light Prime. This is similar in size to the original Limelight with the difference being the change in flower color in the fall. Prime turns a deep pink! This panicle Hydrangea is from Proven Winners and works well in mixed-shrub borders in full sun.

Here is how Limelight Prime looks in the fall. Thanks to Spring Meadow Nursery/Proven Winners for these photos!

My blue Hydrangeas have black buds…should I cut them?

If your blue lacecap or mophead hydrangeas still have black buds at this time of year, it’s likely that those were killed in the winter or during a late-spring cold snap. Unfortunately, these buds contained the germ of the flowers for this summer. If the buds on your Hydrangea canes still are black at the end of May, those canes can be cut to the ground to make way for the growth of new stems from the ground. The plant will be just as tall by the end of summer, but without many flowers. Varieties such as Endless Summer will produce a few new flowers in September or October.

Do the canes of your mophead or lacecap Hydrangeas look like this? If the buds are still black in late-May, they are not going to open and those canes can be removed completely.

How do I prune my blue Hydrangea in May? Is it too late to prune Hydrangeas?

If you haven’t pruned your mophead (Hydrangea macrophylla) or lacecap (Hydrangea serrata or mactrophylla) yet, this is a great time to do so, but be sure not to remove any of the green growth on the stems. Only cut out bare stems that have no leaves on them. Click here to download our Hydrangea Pruning Handout.

Prune Hydrangeas by removing all dead wood – canes that have no green leaves or green buds. The few stems on the left side of this shrub have no flowers or green buds, and should be removed.

Here is a mophead Hydrangea that has been pruned. All dead canes were cut away, but any that had green leaves were left. Do not try and make this plant shorter – they replace their height in one summer, and you’ll have fewer flowers.

How do I take care of my Annabelle Hydrangea in spring?

Annabelle is a variety of Hydrangea arborescens, aka smooth hydrangea. Other varieties of this type are Invincebelle Spirit II, Blush, Mini Mauvette, Incrediball, and Wee White. Since these shrubs sucker to the side, they can be divided at this time of year should they be growing wider than you might prefer. Prune by clipping off any old flowers, removing all deadwood, and by cutting the plant back by a quarter of its height, making the cut above a pair of green leaves.

This is an Annabelle Hydrangea in May. Prune by removing dead canes and old flowers, as well as any canes that are growing horizontally or along the ground, and those that look weak or funky.

Pruning an Annabelle by cutting off the top quarter of the plant, snipping an inch or so above a pair of buds.

My Hydrangea’s leaves and buds turned black! What’s wrong?

Sometimes a Hydrangea starts to leaf out and there is a night when the temperatures drop to freezing, or there are days of cold wind. Either of these can kill or damage the emerging Hydrangea leaves and flowers. You may see this has happened on some of your plants but not others. Usually the damaged plant is in a more exposed location.

Another possible cause of blackened leaf edges or buds is fertilizer burn. This happens when a synthetic fertilizer is applied in too high a concentration, or to a dry plant. A Hydrangea might get fertilizer burn if lawn fertilizer is kicked into the shrub when applied to nearby turf.

In either case, wait and see what happens. The leaves and buds will either recover and go on to grow and bloom, or they won’t. If the effected buds and stems don’t recover and start to grow, they can be cut out in late June.

This Hydrangea bud was killed by a spring frost. It’s likely that the flowers have been killed on the stems that look like this, but since there is no going back in time, the percentage play is to leave the plant and see what happens.

Why does my white Hydrangea have closed leaves on top?

Smooth hydrangeas (Hydrangea arborescens) are prone to the hydrangea leaf tier, a larva that knits the top leaves together to protect itself as it feeds on the foliage. The following photos show how this looks, and what to do. To see a photo of the moth that lays the eggs for the leaf tier, click here.

If you see the top leaves on your Annabelle or other smooth Hydrangea looking like little packets, you’ve got the leaf tier. These typically appear in late May or early June on Cape Cod.

If you open those leaf packets you’ll find the larva inside. Because it is protected inside the leaves, no spray will kill it.

The best control of the Hydrangea leaf tier is to cut off the knitted leaves you see. Put them in a paper bag and burn, bury, or otherwise destroy them. The plant will still bloom well.

Whether you’re tending to your existing Hydrangea shrubs or planting new ones, we’re here to help! Come in and stroll through our Hydrangea section that is refreshed with new stock regularly at this time of year. Discover some of the newer varieties that are smaller. See many of the tree-form of panicle Hydrangeas, as well as the traditional favorites in mopheads and lacecaps.

Posted in Hydrangeas