7 Mistakes You're Making With Your Hydrangeas—and How to Avoid Them

Hydrangeas are deciduous shrubs that boast huge, vibrant clusters of blooms, which put on a show from late spring until fall. Known for being low maintenance, hydrangeas are a popular choice among beginner gardeners and experienced growers alike. But despite their reputation for being easy to care for, there are a few common mistakes home gardeners of all skill levels can make with hydrangeas. Luckily, these pitfalls are easy to prevent when you know what to look for.

Poor Soil Drainage

Hydrangeas prefer well-draining soil that is rich in nutrients. "You've got to give your hydrangea a comfortable home to settle down in, or they can struggle," says Ryan Mcenaney, public relations and communications specialist for Bailey Nurseries and author of Field Guide to Outside Style.  Hydrangeas don't do well in heavy clay soil as it can retain too much water, but you can amend it with gypsum to improve drainage. If you're dealing with sand-like soil, which doesn't retain enough water, try amending it with peat moss to create a better environment for your hydrangeas.

Incorrect pH

The pH of the soil is one of the most important things to be mindful of when caring for hydrangeas. "Getting your soil pH tested before planting your hydrangeas is essential to make changes where necessary," says Laura Root, category manager of live plants at Jackson & Perkins. "Incorrectly adjusting the soil pH can severely limit the uptake of nutrients depending on the direction of adjustment." Not only does soil pH impact plant health, but for some hydrangea varieties, it can also change the color of the blooms. "Typically, blue hydrangeas thrive in acidic soil, whereas pink hydrangeas prefer alkaline soil," says Root.

Too Much Sun

Hydrangeas love morning sun and afternoon shade, and the farther south you get, the more shade hydrangeas will need. "If you live in zone 4, you can get away with almost full sun," says Mcenaney. "But if you live in zones 7 to 9, you really want to restrict the sun exposure to a few hours in the early morning to avoid scorching the leaves and blooms."

Pruning at the Wrong Time

Hydrangeas should never be pruned in the fall. "Hydrangeas set flower buds for the following season in the fall, so if you cut it back, you are cutting off all of the blooms," says McEnaney. Instead, hydrangeas should be pruned in the spring. "It may not be ideal to keep the leafless stems up in the garden, but you want to be sure you're not cutting off any old wood that is dormant because you'll be removing your blooms for early in the season," he says.

Over Fertilizing

If you're fertilizing your hydrangeas weekly, you are feeding them too often. "Adding fertilizer weekly can add too much nitrogen to the soil, which can actually slow bloom production," says McEnaney. Instead, you should fertilize hydrangeas as the plant is first waking up in the spring and one more time in mid-July, as its buds are blooming. "That extra energy will really help with getting more blooms," says McEnaney.

Too Much Water

Hydrangeas are particular with their water intake. While they prefer evenly moist soil, you need to be careful not to give them too much water. "Overwatering your hydrangeas can lead to root rot," says Root. "Hydrangeas need consistent moisture. Do not let the roots stand in water or let the soil dry out in between waterings. Letting them dry out can cause stress to the plant and allow diseases." Depending on your area's natural rainfall, this could mean you may need to water your hydrangeas every day or as little as once a week.

Planting Too Close

When fully grown, hydrangeas are actually pretty large plants—some variations can get as big as 10 feet tall and 8 feet wide. But, of course, when you first purchase your plant, it's going to be much smaller—resist the urge to crowd your new hydrangeas too much. Planting your hydrangea plants too close together can mean that the plants are competing for water and nutrients, potentially causing them to deteriorate.