Hydrangea: Plant Care and Growing Guide

Popular Hydrangea Types

Hydrangeas come in many different types, each with its own unique characteristics. Here is a list of some of the most popular types:

Bigleaf Hydrangea (Hydrangea macrophylla): Also known as mophead or lacecap hydrangeas, these plants have large, rounded flowers that come in shades of pink, blue, or purple. The color of the flowers can be affected by the pH of the soil. They can grow up to 2-6 feet 2-4 feet (60-180 cm) tall and wide.

Oakleaf Hydrangea (Hydrangea quercifolia): These shrubs have large, oak-like leaves and cone-shaped flowers that range in color from white to pink. They are prized for their stunning fall foliage. They can grow up to 3-8 feet (90-180 cm) tall and wide, although some cultivars may be smaller.

Panicle Hydrangea (Hydrangea paniculata): These shrubs have cone-shaped flower clusters that start out white or green and turn pink or red as they age. They are generally easy to care for and are tolerant of a wide range of growing conditions. They can grow up to 3-10 feet (90-300 cm) tall and wide.

Smooth Hydrangea (Hydrangea arborescens): These shrubs have round flower clusters that start out green and turn white as they mature. They are generally very easy to grow and maintain. Annabelle hydrangea and Limelight hydrangea are highly popular. They can grow up to 2-5 feet (60-150 cm) tall and wide.

Mountain Hydrangea (Hydrangea serrata): These shrubs have small, delicate flowers that come in shades of pink, blue, or purple. They are generally more cold-hardy than other hydrangea types. This species can grow up to 2-4 feet (60-120 cm) tall and wide.

Climbing Hydrangea (Hydrangea anomala subsp. petiolaris): This is a vine that can climb up walls or trellises. It has large, flat clusters of white flowers and is known for its striking foliage.

Not sure which hydrangea to pick? Find the best one for your garden with our Plant Finder or discover wonderful choices by participating in one of the American Hydrangea Society tours.

When to Plant Your Hydrangea Bush

The best time depends on your location and the species you are planting. Here are some general guidelines:

• Planting in spring: In cooler climates, it’s best to plant hydrangeas in the spring after the last frost. This will give the plant time to establish itself before the hot summer months.
• Planting in fall: In warmer climates, fall can also be a good time to plant them. The cooler temperatures and higher rainfall can help the plant establish roots before the summer heat.

Where to Plant Hydrangea

Hydrangeas are versatile plants that can be grown in various conditions, although their specific growing requirements can vary depending on the species.

• Light: Most plants prefer partial shade, with some species tolerating full sun and others preferring more shade. In general, the hotter the climate, the more shade your plant will need.
• Soil: They prefer moist, well-drained soil rich in organic matter. They are also sensitive to soil pH, with some species producing blue flowers in acidic soil and pink flowers in alkaline soil.
• Climate: Hydrangeas are generally hardy in USDA zones 3-9, although their specific cold and heat tolerance can vary depending on the species. Some species are more cold-hardy than others, while others prefer warmer climates.
• Space: Hydrangeas can grow quite large, particularly some species like panicle hydrangea (Hydrangea paniculata). Be sure to provide enough space for the plant to grow to its full size without being crowded.

How to Plant Hydrangea

• Choose a planting location: Hydrangeas prefer partial shade, with some species tolerating full sun and others preferring more shade. Choose a location with well-draining soil that is rich in organic matter.
• Prepare the planting hole: Dig a hole that is twice as wide and just as deep as the root ball of your plant. Loosen the soil at the bottom of the hole to allow for better root growth.
• Amend the soil: Mix in some compost or well-rotted manure to the soil at the bottom of the planting hole. This will help to improve drainage and provide nutrients for the plant.
• Remove the plant from its container: Gently tap the sides of the container to loosen the root ball. Carefully remove the plant from the container, taking care not to damage the roots.
• Plant: Place the plant in the center of the hole and backfill it with soil, tamping it down gently as you go. Water the plant thoroughly to help settle the soil.

Hydrangea Care

Hydrangeas require some care to keep them healthy and looking their best.

• Watering: Hydrangeas require regular watering, particularly during dry spells or in hot weather. Water deeply and regularly to keep the soil moist but not waterlogged.
• Fertilizing: To determine if your plant requires fertilization, it’s recommended to conduct a soil test. If your soil is already rich in nutrients, you may not need to apply fertilizer, as too much can lead to excess foliage growth instead of blooms. For best results, apply fertilizer based on the specific needs of your variety. Each type has different requirements and will benefit from different application timings.
• Bigleaf hydrangeas may benefit from several light fertilizer applications in March, May, and June. Oakleaf and panicle hydrangeas, on the other hand, will do best with two fertilizer applications in April and June. Smooth hydrangeas, however, only need to be fertilized once, in late winter.
• Mulching: Mulch around the base of the plant to help retain moisture and suppress weeds. Keep the mulch away from the stem of the plant to prevent rot.
• Winter care: Some species may require protection during the winter months, particularly in colder climates. You can protect the plant by adding a thick layer of mulch (straw, leaves, or pine needles) or covering it with a cloth or burlap.

By following these care tips, you can keep your plants healthy and looking beautiful for years to come.

How to Prune a Hydrangea

Different types of hydrangeas require different pruning techniques, so it’s important to know the specific species you have before pruning.

• Bigleaf Hydrangea: Prune immediately after blooming, cutting back the stems that have finished flowering to a healthy set of leaves. You can also remove old wood in the late winter or early spring to encourage new growth and flowering.
• Panicle Hydrangea: Prune in late winter or early spring before new growth begins and flower buds are formed. Cut back the previous year’s growth to 1-2 buds above the soil line or to a healthy set of leaves. You can also remove any dead or damaged wood at this time.
• Oakleaf Hydrangea: Prune immediately after blooming, cutting back the stems that have finished flowering to a healthy set of leaves. You can also remove old wood in the late winter or early spring to encourage new growth and flowering.
• Smooth Hydrangea: Prune in late winter or early spring before new growth begins and flower buds are formed. Cut back the previous year’s growth to 1-2 buds above the soil line or to a healthy set of leaves. You can also remove any dead or damaged wood at this time.
• Mountain Hydrangea: Prune immediately after blooming, cutting back the stems that have finished flowering to a healthy set of leaves. You can also remove old wood in the late winter or early spring to encourage new growth and flowering.
• Climbing Hydrangea:  Pruned immediately after flowering in the summer. Climbing hydrangeas tend to grow quite slowly, so be patient when pruning and avoid removing too much of the plant.

How to Change the Color of Hydrangea Flowers

Hydrangea flowers can change color naturally depending on the pH level of the soil they’re grown in. However, it’s also possible to change the color of the flowers intentionally.

• Determine the current pH level: The first step in changing the color of the flowers is to determine the current pH level of the soil. Hydrangeas grown in acidic soil (pH below 6.0) tend to produce blue flowers, while those grown in alkaline soil (pH above 7.0) tend to produce pink flowers.
• Changing the pH level: To change blue hydrangea flowers to pink, you can raise the pH level of the soil by adding lime. To change pink hydrangea flowers to blue, you can lower the pH level of the soil by adding sulfur.
• Applying the amendment: Apply the appropriate amendment to the soil in the fall or early spring, as this will give it time to work before the plant starts to produce flowers. Follow the instructions on the package for the amount to use, as over-application can damage the plant.
• Monitoring the pH level: Monitor the pH level of the soil regularly and make adjustments as necessary to achieve the desired flower color.

It’s important to note that not all species respond to soil amendments in the same way, and some may be more difficult to change their color than others. It’s also important to avoid over-fertilizing, as this can lead to excessive foliage growth at the expense of flowers.

Companion Plants

Hydrangeas are beautiful, versatile plants that can be complemented by a range of companion plants. Here are some ideas for plants that pair well with them:

Hostas: Hostas are shade-loving plants. They make an excellent ground cover and can help to fill in gaps in the garden.

Ferns: Ferns are also shade-loving plants. They provide an elegant, feathery contrast to the hydrangea’s broad leaves.

Japanese forest grass: Japanese forest grass is a low-growing, shade-loving ornamental grass. It provides a soft, flowing contrast to the hydrangea’s bold leaves and flowers.

Astilbe: Astilbe is a shade-loving perennial that produces tall, feathery plumes of pink, red, or white flowers that contrast beautifully with hydrangeas.

Bleeding heart: Bleeding heart is a shade-loving perennial that produces delicate, heart-shaped flowers that complement the rounded shape of hydrangea blooms.

How to Propagate

Hydrangeas can be propagated through several methods, including taking stem cuttings, dividing established plants, or layering.

• Stem cuttings: Take stem cuttings in late spring or early summer from healthy, new growth. Cut a 4-6 inch (10-15 cm) section of stem with at least two leaf nodes, remove the bottom set of leaves, and dip the cut end in the rooting hormone. Plant the cutting in a pot filled with moist, well-draining potting mix, and keep it in a warm, humid location until roots have formed.
• Division: Hydrangeas can also be divided by digging up an established plant in early spring or fall and dividing it into smaller sections, each with several shoots and roots. Replant the sections in well-draining soil and water thoroughly.
• Layering: Layering involves bending a lower branch to the ground, making a small wound in the bark, and burying it in the soil. Secure the branch to the soil with a bent wire or stake, and keep the soil moist. Roots will form at the wound, and a new plant will form. Once the new plant is established, cut it from the parent plant and transplant it to a new location.

How to Cut and Store Dried Hydrangea Flowers

Dried hydrangea flowers are a beautiful addition to floral arrangements, wreaths, and other crafts.

• Timing: The best time to cut hydrangea flowers for drying is in the late summer or early fall, after they have reached their full size and have started to change color.
• Cutting: Cut the flowers from the plant with a long stem, leaving several leaves on the stem to help support the flower. Avoid cutting flowers that are still green or have not yet fully opened.
• Drying: Hang the flowers upside down in a warm, dry, and dark location, such as an attic or closet. Make sure the flowers are not touching each other and have good air circulation. The drying process can take up to several weeks, depending on the humidity.
• Storage: Once the flowers are fully dry, store them in a dry, cool, and dark place. Avoid exposing them to direct sunlight or moisture. You can store them in a vase or container or use them in crafts or arrangements.

Dried hydrangea flowers can last for months or even years if stored properly. They can be used in a variety of creative projects, from wreaths to centerpieces, adding a touch of natural beauty to your home décor.

Pest and Diseases

Hydrangeas can be affected by a range of pests and diseases, so it’s important to keep an eye out for any signs of problems. Here are some common pests and diseases that affect them:

Aphids: These small, soft-bodied insects can cluster on the undersides of leaves and cause damage by sucking sap from the plant. Control them with insecticidal soap or neem oil.

Spider mites: These tiny insects can be identified by the fine webbing they leave on the plant. They can cause damage by sucking sap from the leaves. Control them with insecticidal soap or neem oil.

Powdery mildew: This fungal disease appears as a white, powdery coating on the leaves, stems, and flowers. It can be caused by poor air circulation, high humidity, or overwatering. Treat with fungicides or by improving cultural conditions.

Leaf spot: This fungal disease appears as dark spots on the leaves and can cause them to drop prematurely. It can be caused by wet conditions or poor air circulation. Treat with fungicides or by improving cultural conditions.

Bacterial wilt: This disease causes the plant to wilt and die. It can be caused by poor drainage, overwatering, or damage to the roots. There is no cure for bacterial wilt, so remove and destroy affected plants.

To prevent pests and diseases, it’s important to keep your hydrangeas healthy and well-maintained. This includes providing them with the right amount of water and nutrients, pruning them properly, and avoiding overcrowding. By monitoring your plants regularly and taking action at the first sign of trouble, you can help keep your hydrangeas healthy and beautiful.

Frequently Asked Questions

Do hydrangeas like sun or shade?

Hydrangeas prefer partial shade, especially during the hottest part of the day. In hotter regions, they can benefit from some protection from the afternoon sun. However, they still need some direct sunlight to produce flowers, so it’s important to find a balance. Morning sun and afternoon shade is often ideal for most species.

Where should you not plant hydrangeas?

Hydrangeas should not be planted in full sun, especially in hot, dry climates. They do not tolerate standing water, so they should not be planted in low-lying areas that are prone to flooding or waterlogging. Their large, delicate leaves can be damaged by strong winds. They should not be planted in areas that are prone to high winds, such as on hilltops or in open fields.

Do hydrangeas grow back every year?

Most hydrangeas are deciduous, which means they lose their leaves in the fall and go dormant for the winter. However, they do come back to life in the spring, producing new leaves and flowers. As long as they are properly cared for, they can grow back every year for many years.

Are hydrangeas high maintenance?

Hydrangeas can be moderately high maintenance, but it depends on the species, location, and growing conditions. While they do require some attention and care, they are not necessarily difficult to maintain.