How to Grow and Care for Hydrangeas That Yield Big, Beautiful Blooms Every Season

When the summer season peaks, gardeners obsess over a highly-anticipated flowering shrub: hydrangeas. A diverse group of flowering woody shrubs, hydrangeas are beloved for their showy blooms, which are available in a range of beautiful colors. As rapid growers—averaging about 2 feet of growth per year—larger varieties of hydrangeas can reach up to 15 feet tall. Applicable in growing zones 3 to 9, hydrangeas are a low-maintenance plant that, with proper care, will return year after year. To ensure your hydrangeas thrive, we spoke to several gardening experts who share their tips for planting, pruning, propagating, and caring for this striking shrub.

How to Plant Hydrangeas

Plant hydrangeas in early spring or fall when temperatures are mild. Before planting, give your hydrangea a thorough watering while it's still in its nursery pot, then select a location with appropriate sun or shade exposure for the variety you're growing, says Kip McConnell, plant expert for Southern Living Plant Collection.

1. Dig a hole two times the width of the pot.
2. Roughen sides of the hole with a shovel to allow the roots to penetrate the sides and expand beyond the hole.
3. Remove the plant from the pot and loosen or cut any circling roots.
4. Set the plant in the hole so the root ball is at the same depth as it was in the nursery pot.
5. Backfill the hole with existing soil.
6. Water the area thoroughly.
7. Cover the soil surface with 1 to 2 inches of mulch, avoiding the area closest to the stem.

How to Care for Hydrangeas

Hydrangeas are an easy-to-care-for shrub that will thrive when its light, sun, soil, water, temperature, and fertilizer needs are met.

Light

The light requirement for hydrangeas will vary by species and variety, so be sure to reference the care tag prior to planting. With that said, many varieties thrive in full sun to partial shade locations.

Soil

Hydrangeas prefer well-drained soil that has organic matter mixed in and adequate moisture. "Heavy soil can hold too much moisture, encouraging root rot, while soil that doesn't hold moisture can cause their roots to dry out," says McConnell. In areas with sandy soil or dense clay soil, add compost or other organic material, such as shredded leaves or coffee grounds, to the soil to balance it out.

Water

Newly planted hydrangeas should be watered every one to two days (or more during extreme heat and drought conditions). "Water in the morning before the sun has reached its peak, allowing the leaves and roots plenty of time to dry off before the sun sets," McConnell says. Once established, water when the top inch of soil is dry to the touch.

Fertilizer

A general all-purpose fertilizer (look for a 10-10-10 or 12-4-8 ratio) will work well for hydrangeas. Apply a slow-release fertilizer twice per year in spring and early fall. "Apply widely around the drip line of the branches instead of the base of the plant, and cover lightly in soil," says McConnell.

Temperature

Hydrangeas grow best in hardiness zones 3 to 9. "That means, they can survive winter temperatures as low as -40 degrees Fahrenheit to 30 degrees Fahrenheit," says Adrienne Roethling, garden director for Paul J. Ciener Botanical Garden. "Or, they will grow well in most of the 48 contiguous states."

Types of Hydrangeas

As hydrangea care is so dependent on the variety you're growing, it's helpful to know a few of the most popular types.

Hydrangea arborescens

Also known as smooth hydrangea, this variety is a rounded shrub with unbranched stems and round white flowers.

• Size: 3 to 5 feet tall and wide
• Zones: 4 to 9
• Blooms on: New wood
• Soil pH: Does not influence flower color

Hydrangea paniculata

This variety, also referred to as panicle hydrangea, grows cone-shaped flowers that start out as white or lime green and fade to pink.

• Size: 10 feet tall and wide
• Zones: 3 to 8
• Blooms on: New wood
• Soil pH: Does not influence flower color

Hydrangea macrophylla

Commonly known as bigleaf hydrangea, this shrub is typically wider than it is tall. It flowers in milder areas in June with repeat bloomers appearing in mid summer.

• Size: 3 to 6 feet tall and wide
• Zones: 5 to 9
• Blooms on: Old wood
• Soil pH: Acidity influences flower color; blue flowers form in acidic soil and pink flowers form in alkaline soil.

Hydrangea quercifolia

Known as oakleaf hydrangea, this variety provides multi-seasonal interest as its cone-shaped flowers fade to pink then brown.

• Size: 8 feet tall and wide
• Zones: 5 to 9
• Blooms on: Old wood
• Soil pH: Does not influence flower color

How to Prune Hydrangeas

In order to understand the pruning needs of your hydrangea, it's important to know whether you're growing a variety that blooms on new wood or old wood. "Old wood hydrangeas will produce some flowering buds in fall whereas those that flower on new wood, will have buds that appear in spring," says Roethling. Note: all hydrangeas can be pruned to maintain size and shape.

Old Wood

Certain species bloom on old wood, so their blooms develop on stems produced during the previous growing season. "Prune these varieties in summer, after they finish blooming to ensure that you don't remove new buds in spring before they bloom," says McConnell. Remove up to one-third of the stems, taking off the weakest shoots. Keep several stems of old productive wood and strong new stems, which will flower next season to encourage growth.

New Wood

Other species bloom on new wood—the current year's new stems—and typically benefit from pre-spring pruning. For these types of hydrangeas, it's best to cut stems back to the ground in late winter or early spring.

How to Propagate Hydrangeas

The easiest way to propagate hydrangeas is by taking cuttings of a branch that hasn't flowered yet, which ensures more energy is placed into rooting, says Roethling.

1. Cut off about 6 inches of a branch with no flower buds and at least one node (the area where the current stem connects with another stem).
2. Dip the cut end into a hormone rooting powder.
3. Fill a pot with well-draining soil.
4. Bury the powder-dipped end 2 to 3 inches below the surface of the soil.
5. Place it in indirect light.
6. Keep soil lightly moist until roots develop (two to three weeks), at which time it will be ready to plant.

How to Grow Hydrangeas in Containers

Most hydrangeas will grow best in the ground, but some Hydrangea macrophylla varieties can be grown in containers, says Roethling. Care is similar to growing hydrangeas in the ground, but you may need to water more often, as the soil will dry out faster in containers. Hydrangea roots will grow very quickly in containers, so every fall, it's best to take the plant out of its pot and gently stretch the roots apart so they no longer take on the shape of the pot. "Pry circling or entangled roots apart and cut about a third of the roots off," says Roethling. "Place the hydrangea back in the pot and backfill new soil around the roots with your fingers, filling it up to just a 1/2-inch below the top of the rim." 

How to Get Hydrangeas to Bloom

Hydrangeas typically bloom from early summer throughout fall. If your hydrangeas aren't blooming, check that the plant is getting adequate sunlight and isn't being over- or under-watered. "If one were to provide the right growing conditions, perform the maintenance tasks at the right time, and provide sufficient fertilizing and watering, little to no extra care is needed to get your hydrangeas to bloom," says Roethling. If your hydrangea flowers start to turn brown or look shriveled after blooming, cut them off with clean, sharp pruners to encourage new, healthy growth.

How to Overwinter Hydrangeas

If you live in an area that experiences all four seasons, your hydrangeas will benefit from winter care. "Water well before the ground freezes, and apply a layer of compost to provide long-lasting nutrients that will sustain the plant through winter," says McConnell.

Next, protect vulnerable roots with a thick layer of mulch. Remove the heavier coat of mulch in spring after the last frost. When snow or ice is anticipated, protect the hydrangea's branches with a gentle cover made of breathable material, like cloth or burlap.

If you're growing hydrangeas in containers, the soil will freeze more than ground temperatures. "Placing the containers in the garage, basement, or even against the house could keep the pots slightly warmer," says Roethling. "Some may choose to wrap the pots in burlap for extra protection."

How to Change the Color of Hydrangeas

Adjusting the acidity or alkalinity in your soil can influence the color of your hydrangeas. If you want to try this, start by testing the pH of your soil; you can buy a simple tester online or from your local nursery. "The lower the pH, the more blue hydrangeas become, and the higher the pH, the more pink they become," says Roethling." For blue blooms, you need acidic soil (pH lower than 7), which can be achieved by adding sulfur or aluminum sulfate. For pink blooms, your soil must be alkaline (pH higher than 7), which can be achieved by adding lime (the mineral, not the fruit!) to the soil.

How to Harvest Hydrangeas

If you want to harvest your hydrangeas for flower arrangements, timing is everything. "If cut too soon, the young blossom will curl and if cut too late, mature blossoms will fall apart," says Roethling. Cut them when the flower head is open and the color is developed. Cut the stems well below the flowers and remove the lower leaves, then place the stems in a clean vase with water.

Common Problems With Hydrangeas

Despite being easy to care for, there are a few common problems gardeners run into when growing hydrangeas.

Powdery Mildew

Powdery mildew is a common disease that plagues hydrangeas. "The white fungus blocks sunlight from reaching the leaves, and in severe cases, the leaves may yellow, brown, and drop off," says Myers. Mildew formation is more common in shaded and overcrowded areas.

To prevent future infections, reduce humidity and improve the plant's air circulation through pruning. Treat the disease with a fungicide labeled for this type of infection. "Start treating at first sign of the disease and repeat as recommended on the product label," Myers says.

Bacterial Leaf Spot

Another disease hydrangeas are susceptible to is bacterial leaf spot. This is especially true for oakleaf and panicle varieties. "The disease presents as dark brown spots that appear to be wet with highly defined edges, appearing on both sides of the leaf as the tissue rots," says McConnell. Prevent it by improving circulation through pruning and avoiding overly saturating your soil with water. The disease can be treated with copper bactericides, which can be found at nurseries and garden centers.

Aphids

An aphid infestation presents as yellowing or withering of the plant's leaves. "At first glance, no visible culprit may appear, but flipping over the leaves will reveal clusters of the tiny green or black pest beneath the leaves," McConnell says. "To treat for aphids, simply wash the leaves in an insecticidal soap or hit the affected leaves with a strong spray from a garden hose."

Beetles

Another pest that affects hydrangeas is beetles. "Several types of beetles may afflict hydrangeas, including Japanese beetles and rose chafer beetles," McConnell says. Start by identifying the type of beetle you're dealing with, which will determine your treatment plan.

For rose chafers and Japanese beetles, remove the bugs by hand and submerge the leaves in warm soapy water. Prevent future infestations by applying neem oil to the leaves.

Month-by-Month Hydrangea Care Guide

It can be hard to keep track of the monthly care requirements for hydrangeas. To help, we put together this monthly guide that lets you know when to fertilize, prune, and more.

Month	Care Requirements
March	Prune hydrangeas that bloom on new wood by cutting plant back about one-third of its total height. Begin fertilizer routine, using a granular option specially designed for woody plants.
April	Continue your monthly fertilizer routine and keep greenery away from garden pests. If you have a hydrangea variety that changes color based on the pH, get your soil tested.
May	If you have an established fertilizer schedule, apply another round now. Put down a 2-to-3-inch layer of shredded bark mulch around the roots to keep hydrangeas cool and moist in the coming heat.
June	Administer another round of fertilizer. You may also need to begin providing supplemental water during June if the weather is hot and dry.
July	You will begin to see the fruits of your labor in July, as the varieties that bloom on old wood peak; types that required a heavy pruning to blossom on new wood should also begin to flower. Now is also a smart time to deadhead any early bloomers to encourage more growth.
August and September	You shouldn't fertilize your plants after July, so this month, you are free to admire your hard work. The hydrangeas can be snipped and displayed as cut colors during this time, if you wish.
October	Your hydrangea has most likely gone dormant at this stage of the year and needs little to no attention. Remove and discard any foliage with leaf spots to minimize the chance of reinfection next year. Use October to top off your mulch to maintain a 2-to-3-inch layer for added winter protection. You can also prioritize pruning hydrangeas that bloom on old wood this month.
November to February	If you have an old wood blooming variety, your work is done for the season, since it will remain dormant through February. If you have a hydrangea variety that blooms on new wood, you can also cut them now (or wait for March).