Pruning hydrangeas now for maximum blooms in summer

By Lynette Walther | Apr 30, 2020
Photo by: Lynette L. Walther Reblooming hydrangeas can bloom more than once a season when given the proper care and conditions. Fertilizing now is key.

If there’s one good thing we can do while staying at home and social distancing — its gardening. Anticipation of billowing mounds of hydrangea blooms is on our minds these days as many of us contemplate the task of pruning these gorgeous flowering shrubs. Hydrangeas are clearly one of the joys of summer.

The daffodils may be sprouting and the days are warming, birds chirping, snow melting and for many, that makes us want to get those pruners out and do a little trimming. As we eye those lifeless-looking sticks and stubs of our hydrangeas it is easy to give into the temptation to cut them back and clean them up.

But hold on there! When it comes to hydrangeas, however, incorrect pruning is the biggest reason for lack of flowers. That’s because we prune them at the wrong time. So let’s get it straight once and for all.

It matters how and when we prune and what variety of hydrangea we are pruning. From the National Gardening Bureau comes this handy guide to hydrangea pruning from Lorraine Ballato author of “Success With Hydrangeas: A Gardener’s Guide.”

Flower Shape and Foliage Clues

If they are not labelled, tell hydrangeas apart by noticing the flowers and/or foliage. If the flowers are big, round, and either white or shades of pink, and it blooms early in the season, it is a woodland or smooth hydrangea. Botanically it’s known as hydrangea arborescens. Varieties like ‘Annabelle,’ ‘Incrediball®’ and ‘Invincibelle® Spirit’ are among the woodland hydrangeas in today’s market. Woodland hydrangeas never have blue flowers.

Flowers that are football- or cone-shaped, are either a panicle or oak leaf hydrangea. Flowers start out cream, white or green, and age to shades of pink. No blue flowers ever on either of these two varieties. If the foliage looks like an oak tree leaf, the hydrangea is an oak leaf hydrangea

When to prune hydrangeas

If the foliage looks like an oak tree, you have an oak leaf hydrangea. How’s that for an easy identification? You might have ‘Alice’, ‘Snowflake’, or “Snow Queen’ among others. The oak leaf hydrangea flowers this year on the growth it put on last year, i.e., old wood.

Panicle hydrangeas (‘Limelight,’ ‘Vanilla Strawberry™,’ ‘Strawberry Sundae®,’ etc.), on the other hand, flowers on the wood it will grow in the coming months, i.e., new wood.

New wood flowering hydrangeas (woodland and panicle) are the only ones you should be cutting now. All the other flowers on old wood. If you cut the old wood bloomers too early, i.e., now, you risk losing flowers.

How much to cut

Cut woodland hydrangeas down to about 18 to 24 inches. But don’t go further than that, if even that much. Strong stems are needed to hold up the flowers, especially after a rainstorm. The older the stems are, the stronger they become. Leave up a few taller stems to form a supporting framework. They will disappear into the plant once it leafs out.

For panicle hydrangeas

Cut these down by at least one-third. Take even more if the plant has become distorted from snow load and other causes.Be comforted in knowing it’s very hard to make a mistake when it comes to pruning new wood hydrangeas. They are very forgiving in that they always grow back and fill in.

Old wood hydrangeas

Old wood hydrangeas come in a few varieties. Some have round flowers that sometimes change to shades of pink or blue. They can either be mountain hydrangeas (serrata), or big leaf hydrangeas (macrophylla). Climbing hydrangeas (petiolaris) and oak leaf hydrangeas (quercifolia) also flower on the growth they produced last year.

Develop an eye for “broccoli”

Little buds on old wood hydrangeas are called “broccoli.” For all old wood hydrangeas, with the exception of dead, diseased or damaged wood, hold off cutting until the little buds called “broccoli,” form. It’s only when those buds emerge that you will know which stems to discard.

However, to a plant back because it has outgrown its allotted space — go ahead and prune. Just be aware that blooming may not occur. A point to remember is that some people never cut their old wood hydrangeas and the plants do just fine.

Keep in mind there’s no guarantee of flowers from old wood hydrangeas if a plant has lost its buds to weather or whatever. Many areas had a rapid and deep freeze in November before the hydrangeas had a chance to harden off. There is a prevalent fear that cold spell killed the buds that were already formed. Nevertheless, even without flowers, the bush will green up handsomely.

Reblooming hydrangeas

Here’s the saving grace. With a big leaf or mountain hydrangea that reblooms (not possible on oakleaf and climbing), expect to get flowers from that plant even if the terminal buds were destroyed.

Rebloomers have the amazing genetics to produce flowers on new stems they will generate in the current season as well as along the stems of last year’s growth.

Reblooming hydrangeas will bloom twice in one year

Give these hydrangeas the proper cultural conditions to do that. The right amount of fertilizer (applied now), moisture, and light (part sun) will keep them happy. Then they can concentrate on mid-season flower production. Some work now will reap big blooming benefits in the months to come.

Lynette L. Walther is the GardenComm Gold medal winner for writing and a five-time recipient of the GardenComm Silver Medal of Achievement and the National Garden Bureau’s Exemplary Journalism Award. Her gardens are in Camden.

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Comments (1)
Posted by: Barry P King | May 01, 2020 07:50

Hi Lynette,

 

The deck at our house has expanded its footprint over time. The hydrangeas under the deck edge now. Is it possible to dig them up and move them? Our dooryard is shady for most of the day with strong afternoon sun for about 3 hours in their current location. If Jen were to wake up one morning and find the hydrangeas had migrated to a different part of the yard would that be grounds for divorce?

 

Signed,

Treading into the unknown.



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