How to Care for Hydrangeas
Plant Guide
Prized for their full, plentiful blooms and hardy disposition, hydrangeas are one of the most popular flowering shrubs in the world. Cultivated in the United States since the 1700s, these perennials can be grown outdoors successfully in Zones 3-7. With lush foliage and large flower heads that last from spring to early fall, hydrangeas are beautiful and versatile landscape staples.
With the right conditions, you can easily grow your own stunning hydrangea plant. In addition to a long bloom season, their clippings can be dried and enjoyed in your home for months at a time. Some hydrangeas even delight with beautiful fall foliage, giving them year-round interest. If you follow these simple planting instructions, you will set your hydrangea up for longevity and years of big and bountiful blooms.
In order for your hydrangea to live its best life, it’s important to choose the right plant for your landscape. The different types have varying needs and characteristics. Whether your yard is sunny or shady or you prefer blue or pink blooms, you will want to do some research in order to select the perfect shrub for your needs.
If you have ample space and are looking for a privacy shrub, oak leaf hydrangea can grow up to 6 feet tall and 6 feet wide. Alternatively, dwarf hydrangeas such as 'Little Lime' make wonderful container plantings. There are several types of hydrangeas to choose from:
Ground Rules
Light
Generally, hydrangeas thrive in partial sun. Ideal conditions would allow for full sun in the morning with filtered light and shade in the afternoon, when the sun is at its peak.
The only species that can survive in full sun is the panicle hydrangea.
Water
The amount of water depends on the amount of sunlight your shrub receives. Hydrangeas require more water than other shrubs but do not like overly wet soil.
Overwatering shows the same symptoms as underwatering. Flowers may wilt, leaves will turn yellow, and the production of new flower buds will diminish if your hydrangea is receiving too much water.
Soil
Hydrangea shrubs require moist and well drained soil. They are not picky and can thrive in a variety of soil types; however, overly dry soils or soils that retain a lot of water such as heavy clay should be avoided.
Bigleaf hydrangeas change color based on the soil’s pH. For blue blooms, use acidic soil with a pH of 5.5 or less (see Espoma Soil Acidifier). For pink blooms, use alkaline soil with a pH of 6.5 or more (see Espoma Garden Lime).
Oakleaf hydrangeas are one of the only hydrangeas that can tolerate dry soil.
Food
Add organic matter or fertilizer to the soil in spring or early summer. Hydrangeas go dormant in the fall so do not add any fertilizer after August.
Temperature
Although hydrangeas are largely heat-tolerant, most varieties prefer cooler temperatures and partial shade. Zones 3-7 are ideal for most hydrangeas.
If you live somewhere dry and hot, oakleaf hydrangea is your best candidate.
Smooth hydrangeas are the best cold climate hydrangeas.
Toxicity
Hydrangeas are toxic to people and pets. In order for hydrangea to cause poisoning, its leaves, buds, or flowers would need to be consumed in large quantities.
Mulch
Maintain 3 inches of mulch in your flower bed to retain moisture and regulate soil temperature. Keep the mulch line about 4 inches from the base of your plant to prevent stem rot.
Planting Process
- Unbox, place outdoors in shade, water thoroughly while still in nursery pot.
- Choose location based on light requirements, soil type, and mature size.
- Prepare the soil and dig a hole twice as wide as the root ball but not deeper.
- Place your hydrangea in the center and backfill with a 50/50 combination of your existing soil and topsoil or compost.You should still be able to see the soil line of the original pot when you are finished planting.
- Water deeply 3 times a week while roots are being established. Thereafter, water to keep soil moist and according to your climate conditions.
- Lightly dress with chemical or organic fertilizer once or twice in the summer. Do not fertilize after August when your plant prepares for dormancy.
How to Plant Hydrangeas
When you first receive your hydrangea, carefully unbox it and place it in a shady part of your yard. Your plant has just gone through some shipment shock so it will take a day or two to acclimate to the sunlight again. Make sure you monitor watering carefully while it is still in its nursery pot and before planting so the soil does not dry out completely.
Hopefully you have already chosen a hydrangea based on your specific planting needs so the next step is to prepare the planting site. Dig a hole twice the size of your root ball but no deeper.
Place your hydrangea in the center and backfill with a combination of your existing soil and topsoil, depending on your soil condition. In order to prevent stem rot and allow for air circulation to the plant, the top of the existing soil from your rootball should still be visible after backfilling.
Add about 3 inches of mulch to your hydrangea flower bed but leave about 4 inches from the base of the plant to prevent trunk rot.
Generally, you should water your new plant 2 or 3 times a week during its growing season. In the peak of summer, a slow and steady trickle is ideal so the water permeates deeper, enabling the root system to grow stronger.
When to Plant Hydrangeas?
How to Prune Hydrangeas?
How to Deadhead Hydrangeas?
Types of Hydrangeas
| Common Name | Botanical Name | Native | Noteworthy Characteristics | Types |
|---|---|---|---|---|
| Bigleaf Hydrangea | Hydrangea macrophylla | Non-native, Japan origin | Includes mophead, lacecap, and mountain varieties | Cherry Explosion, Endless Summer |
| Climbing Hydrangea | Hydrangea anomala | Non-native, Asia origin | Vine, prefers shade | Climbing Hydrangea Vines |
| Oakleaf Hydrangea | Hydrangea quercifolia | Native to the U.S. | Large, oak-shaped leaves, fall foliage, can tolerate dry soil | Ruby Slippers, Snow Queen |
| Panicle Hydrangea | Hydrangea paniculata | Non-native, Asia origin | Can tolerate full sun | Limelight, Little Lime |
| Smooth Hydrangea | Hydrangea arborescens | Native to the U.S. | Can tolerate hotter climates | Annabelle, Incrediball |