What to Do With Hydrangeas in May to Guarantee a Spectacular Display in the Summertime
Hydrangeas have now entered their active growth period – do these essential tasks in May to help them produce gorgeous blooms
May is a crucial time for hydrangeas: as spring inches toward summer, these classic shrubs are preparing to burst into flower. With this in mind, now is the time for regular feeding, watering, and mulching – all of which will ensure strong growth and long-lasting blooms.
It's also important to hold off on hard pruning this month, as it could destroy new buds. Knowing how to grow hydrangeas means paying careful attention to monthly tasks – and understanding what to do with hydrangeas in May is all about prioritizing water, nutrients and soil health.
1. Avoid Hard Pruning
'May is a busy time for hydrangeas, but depending on which kind of hydrangea you have, you could ruin your season by pruning,' warns Lorraine Ballato, author of Success with Hydrangeas.
It's crucial to know when to prune hydrangeas, and timing is also dependent on location.
'Unless you garden in an extremely cold zone (like northern Canada and some parts of the U.S), pruning now will likely deprive you of seasonal flowers,' says Lorraine.
While most pruning should be reserved for dormant periods – such as immediately after flowering, or during late winter – you'll still want to cut back damaged stems in May. You can use essential pruning tools like the Okatsune bypass pruners, which you'll find at Amazon.
'The only pruning you should do in May is removing dead, diseased, damaged, and dysfunctional stems,' confirms Lorraine.
Lorraine Ballato is a hydrangea expert and the the author of the international best selling book 'Success with Hydrangeas', available at Amazon. She is also an in-demand speaker throughout the US and the resident hydrangea expert at the New York Botanical Garden.
2. Start Deep Watering
As temperatures pick up and your hydrangeas prepare to bloom, steady watering is key.
'Irrigation should be slow and deep rather than frequent and shallow,' says Lorraine. 'You want the roots to go down into the soil to find the water so they don't parch and dry out when things get hot.'
To help you monitor moisture levels throughout the season, you can invest in a soil moisture meter, like this one from Walmart – or simply check by hand.
'I like to determine how much to water using the so-called knuckle test: the soil should be damp at your second knuckle', says Lorraine. 'If it isn't, you should start watering. Repeat the test a few hours later to determine if your soil is water retentive.'
3. Prioritize Feeding
Wondering when to fertilize hydrangeas? Spring is the best time, since their active growth period is well underway – so you'll want to start feeding yours in May if you haven't already.
It's best to choose an all-purpose fertilizer (like the Miracle Gro all-purpose plant food from Home Depot) or rose fertilizer (like the BioAdvanced rose and flower care from Amazon).
Avoid high-nitrogen fertilizers, as these can encourage hydrangeas to produce leafy growth rather than flowers.
'It's important to fertilize with a granulated shrub product or rose food – as strange as that may sound,' says Lorraine. 'The micronutrients in these formulas are essential for hydrangeas in the springtime.'
When it comes to application, wait until your hydrangeas show their first new leaves, then fertilize once. (Though you can fertilize again in mid-summer if needed.) Sprinkle the fertilizer around the drip line rather than against the stems.
4. Don't Forget to Mulch
Hydrangeas thrive in moist, slow-draining soil; to give them a boost in the springtime, you'll want to supplement this with plenty of compost and mulch.
'If you find your soil drying out, incorporate compost to aid moisture retention,' advises Lorraine. 'Mulching is crucial: you'll need about 2-4 inches. This will also protect the roots of your hydrangeas.'
You can stock up on organic premium compost at Amazon, and find organic natural mulch at Home Depot.
In need of more advice? We asked experts to debunk the most common hydrangea myths – and explain why hydrangea flowers turn brown.
And if you love inspiring garden ideas, outdoor advice, and the latest news, why not sign up for our newsletter and get the latest features delivered straight to your inbox?
