How to Grow and Care for Hydrangeas in Pots

Compact and dwarf hydrangea varieties make great container plants

You don’t need a large yard to enjoy growing hydrangeas. These lovely shrubs can grow in containers in many places, from porches and decks to driveways and sidewalks—even on a balcony. The key is to select a small, compact hydrangea variety and put it in a location where it gets at least four hours of sun each day.

All hydrangeas are toxic to humans and pets.

Hydrangea Care

Caring for potted hydrangeas is very similar to hydrangeas in the landscape, with the exception that they need more frequent watering and fertilization.

Light

Hydrangeas need full sun, dappled sun, or partial shade. Not all types have the same sun tolerance. Mountain, smooth, panicle, and bigleaf hydrangeas do best in a location where they receive four to six hours of sun per day. Panicle hydrangeas are still fine with six or more hours of sun. Generally morning sun is preferable to afternoon sun, especially in a warm climate.

When planting a large hydrangea, keep in mind that the container will be heavy after it is filled with soil so place it in a spot with the right light conditions before filling it (unless you have a caddy to move it).

Soil

Choose a lightweight, high-quality potting mix (not soilless seed starting mix) and combine four parts potting mix with one part compost.

The soil acidity of some hydrangeas can be changed but that’s a tricky thing to do with potted plants, as you need to know the actual pH of the soil in order to amend it. In the landscape, you can soil test but unless you want to go through that trouble for a container, it is much better to start off by planting a hydrangea variety that has the desired color.

Water

Keeping your potted hydrangea watered cannot be overstated because, unlike hydrangeas in the landscape, container plants dry out fast. Make sure to check the soil every day; when the top inch of soil feels dry (do the finger test), it’s time to water. Water the entire soil until water drips out of the drainage holes. On a hot summer day, it is not unusual for a hydrangea to need watering even twice a day. And the more sun exposure it has, the more water it needs.

Temperature and Humidity

Just like in the landscape, hydrangeas do not tolerate temperature extremes, both scorching hot summers, and extremely harsh winters. Select a protected spot for your container-grown hydrangea. A north- or east-facing site where winter temperatures remain somewhat constant is best because the hydrangea does not receive too much winter sun, so it won’t be coaxed into budding early during a warm spell.

Hydrangeas are tolerant of moderate to high humidity but not of a dry, hot climate.

Fertilizer

Because potted hydrangeas are watered more frequently, which washes out the nutrients, it needs regular fertilizing. Use an all-purpose granular slow-release fertilizer for flowering shrubs or for acid-loving plants if your hydrangea has blue flowers. Apply it once in the spring as the plant breaks dormancy. Scatter it around the soil but keep it away from the branches. Water it in thoroughly. Continue fertilizing the plant monthly but stop in the late summer because any new growth is more susceptible to cold damage when the first frost hits.

Types of Hydrangeas

When it comes to hydrangeas for containers, size is everything. Here is a selection of hydrangeas that are suitable for long-term container-growing:

• Invincibelle Wee White smooth hydrangea (Hydrangea arborescens ‘NCHA5’). White flowers; 1 to 2.5 ft. tall and 2-3 ft. wide; zone 3-8.

• Invincibelle Ruby smooth hydrangea (Hydrangea arborescens ‘NCHA3’). Pink flowers; 3-4 ft. tall and 2-3 ft. wide; zone 3-8.

• Wee Bit Grumpy bigleaf hydrangea (Hydrangea macrophylla ‘Wee Bit Grumpy’). Purple or red flowers; 2 ft. tall and 2.5 ft. wide; zone 5-9.

• Let's Dance Can Do! reblooming hydrangea (Hydrangea macrophylla × serrata). Violet-purple to pink flowers; 3-4 ft. tall and 3 ft. wide, zone 4-9.

• Paraplu bigleaf hydrangea (Hydrangea macrophylla 'Paraplu'). Pink flowers; 2.5 to 3 ft. tall and wide; zone 5-9.

• Cityline Paris bigleaf hydrangea (Hydrangea macrophylla 'Paris Rapa'). Red-pink flowers; 1-2 ft. tall and 1-3 ft. wide; zone 5-9.

• Cityline Rio bigleaf hydrangea (Hydrangea macrophylla 'Ragra’). Blue flowers. 2-3 ft. tall and wide; zone 5-9.

• Pop Star bigleaf hydrangea (Hydrangea macrophylla 'Bailmacsix'). Blue, pink, or purple flowers; 1.5 to 3 ft. tall and wide; zone 4-9.

• Little Quick Fire panicle hydrangea (Hydrangea paniculata 'Little Quick Fire'). White flowers turning pink in late summer; 3-5 ft. tall and wide; zone 3-8.

• Little Lime panicle hydrangea (Hydrangea paniculata 'Little Lime'). Greenish flowers turning pink in the fall; 3-5 ft. tall and wide; zone 3-8.

• Bobo hydrangea (Hydrangea paniculata 'Bobo'). White flowers; 2-3 ft. tall, 3-4 ft. wide; zone 3-8.

• Tiny Tuff Stuff mountain hydrangea (Hydrangea serrata 'MAKD'). 1.5-2 ft. tall and wide; blue or pink flowers; zone 5-9.

Pruning

For pruning, is important to know which type of hydrangea you have. Some species of hydrangea bloom on old wood, while others bloom on new wood, and yet others bloom on both. The bloom time determines when to prune them:

• Smooth hydrangeas bloom on new wood and are pruned in late winter or early spring.

• Panicle hydrangeas also flower on new wood, which means late winter or early spring pruning.

• Bigleaf hydrangeas bloom on old wood and are pruned after the end of the bloom period.

• Mountain hydrangeas bloom on old wood but don’t need much pruning; if at all, prune them immediately after flowering.

• Repeat blooming hydrangeas should not be pruned other than removing faded blooms or dead and diseased branches.

Whichever hydrangea you have, follow these detailed step-by-step pruning instructions.

Propagating Hydrangea

Most hydrangea cultivars that have been bred for container-growing are trademarked or patented cultivars and propagating them in any form is prohibited.

Potting and Repotting Hydrangea

Choose a pot that is at least 16 to 24 inches in diameter, or large enough to fit the root ball of the hydrangea. Make sure that it has large drainage holes. As pretty as they are, terracotta and ceramic containers are problematic because they can crack during the winter.

To hold the soil in the container, you can line the bottom with a piece of fine screen mesh. Add a layer of potting mix and compost, enough so that when you place the hydrangea in the pot, the top of the root ball sits slightly below the rim of the container. Remove the plant from its nursery pot and place it in the container. Add soil around the root system and tamp it down as you go. Water it thoroughly. Cover the soil with mulch to preserve soil moisture.

Depending on the growth rate. repotting of the hydrangea to a larger container will be necessary after three to five years when the roots reach the sides of the container, and the plant stops growing.

Overwintering

Even if your container-grown hydrangea is a variety that is winter-hardy in your zone, you will most likely have to winterize it. Moving the container to a location where it is protected from damaging winter winds might not be enough. Simply moving the plant indoors, however, is not an option, as the hydrangea needs to go through its natural winter dormancy to maintain its natural rhythm.

The most vulnerable parts are the roots, which are exposed in a container, so they need to be insulated from the cold. You can either bury the container in the soil before the ground freezes, which of course is only feasible for smaller pots. Or you can build an insulation silo by placing the container in a larger container filled with mulch or straw. Another option is to wrap the container with several layers of bubble wrap or burlap.

Keep in mind that terra cotta containers may crack during freeze-and-thaw cycles.

Common Pests and Plant Diseases

Potted hydrangeas are susceptible to the same pests as hydrangeas in the landscape, which include aphids, black vine weevils, Japanese beetles, and spider mites. Minor infestations can be treated with insecticidal soaps.

Hydrangeas are also susceptible to plant diseases including botrytis blight, powdery mildew, cercospora leaf spot, as well as viruses such as yellow or brown leaf spotting. Fungal diseases are more likely to occur when there is not enough air circulation in a confined, crowded space, and the hydrangea is placed too closely to other plants. Also avoid overhead watering of your hydrangea and always water at the base. Wet foliage that lingers can exacerbate the spreading of fungal diseases.

How to Get Potted Hydrangea to Bloom

If a hydrangea fails to bloom, it is usually lack of sunlight. Too much shade can reduce flowering. Try to move your plant to a sunnier spot (while making up for the increased evaporation with more frequent watering, as needed).

Florist hydrangeas—small potted mophead hydrangeas that you buy when they are in full bloom—often don’t bloom again. These plants were forced into flowering to serve as short-term showy centerpieces or gifts. They are not meant to be grown as long-term plants, either in pots or in the landscape.

Frequently Asked Questions

Can potted hydrangeas stay outside?

If you have a hydrangea that is winter-hardy in your climate zone, it can remain outside during the winter. But unlike hydrangeas that were planted in the ground, it’s roots will require protection from the winter chill (see Overwintering above).

Can hydrangea recover from frost damage?

Most hydrangeas are winter-hardy (with the exception of florist hydrangeas), and it will re recover from late spring frost or early fall frost damages. Wait until the weather has warmed up before removing the damaged foliage.

How long can hydrangeas live in pots?

In adequate soil, a container that allows growth, and with the proper watering and fertilization, hydrangeas can live in a pot for years until they outgrow it, at which point they need to be repotted. The exception are florist hydrangeas, which have a much shorter and only seasonal life cycle at best.

Read Next: How to Prune Hydrangeas