How to Plant and Care for Hydrangeas: A Comprehensive Guide

Hydrangeas, with their lush blooms and vibrant colors, are a garden favorite for many. These versatile shrubs can add a touch of elegance and charm to any landscape. Whether you’re a seasoned gardener or just starting out, understanding how to properly plant and care for hydrangeas will ensure healthy growth and abundant flowering. This guide provides a comprehensive overview of hydrangea care, ensuring your garden flourishes with these beautiful plants.

:max_bytes(150000):strip_icc()/growing-hydrangeas-1402684-03-e11232b1f467492f8f8f053c01786cb7_1-0c3fba0657ea482daed2a4f9a93e9f07.jpg)

Choosing the Right Time and Location for Planting Hydrangeas

The ideal time to plant hydrangeas is in late spring or early fall. This allows the root systems to establish themselves before the stresses of extreme summer heat or winter frost. When selecting a location, consider the following:

Sunlight: Hydrangeas thrive in partial shade, particularly with morning sun and afternoon shade. While some varieties can tolerate full sun, they may require more frequent watering, especially in hotter climates. Too much shade, however, can reduce flowering.
Soil: Well-drained, moist, and humus-rich soil is crucial for hydrangeas. Amend heavy clay or sandy soils with compost to improve drainage and fertility.
Space: Consider the mature size of your hydrangea variety when planting. Ensure adequate space for air circulation and growth, typically 2 to 6 feet wide and 2 to 20 feet tall depending on the type.

Step-by-Step Guide to Planting Hydrangeas

Dig the Hole: Dig a hole twice as wide as the hydrangea’s root ball and just as deep. This wider hole encourages root spread.
Prepare the Root Ball: Gently remove the hydrangea from its nursery pot and loosen any circling roots. This encourages the roots to grow outwards into the surrounding soil.
Planting Depth: Place the root ball in the center of the hole, ensuring the top of the root ball is level with the surrounding soil surface. Planting too deep can lead to stem rot.
Backfill and Water: Backfill the hole with the amended soil, gently firming it around the root ball. Water deeply immediately after planting to settle the soil and hydrate the roots.

:max_bytes(150000):strip_icc()/growing-hydrangeas-1402684-04-5ffb78bb30e0442a8542f982f30ef749_1-8634c6f481ea48a0a134008742aac9bb.jpg)

Watering Hydrangeas for Optimal Growth

Water is a critical element in hydrangea care. They require consistent moisture, especially during their growing and blooming seasons.

Deep Watering: Water deeply one to two times per week, providing a thorough soaking that reaches the root system. Avoid light, frequent watering which only wets the surface and doesn’t encourage deep root growth.
Check Soil Moisture: Before watering, check the soil moisture by inserting your finger about four inches deep. If it feels dry, it’s time to water.
Avoid Soggy Soil: While hydrangeas need moisture, they don’t like to sit in soggy soil. Ensure good drainage to prevent root rot.
Adjust Watering: Reduce watering after heavy rainfall and increase it during hot, dry periods. Be mindful of potted hydrangeas, which tend to dry out faster than those planted in the ground and may need more frequent watering.

Understanding Hydrangea Soil and pH for Bloom Color

Soil plays a significant role in the color of certain hydrangea varieties, particularly Hydrangea macrophylla (bigleaf hydrangeas).

Soil pH and Flower Color: Acidic soils (pH 6.0 and below) promote blue blooms, while alkaline to neutral soils (pH 7.0 and above) encourage pink to red blooms. White hydrangeas are not affected by soil pH.
Adjusting Soil pH: To encourage blue blooms, amend the soil with soil sulfur or aluminum sulfate to increase acidity. To encourage pink blooms, add lime to the soil to increase alkalinity. Soil testing kits are available to accurately measure your soil pH.
Fertilizing for Color: Use fertilizers formulated for acid-loving plants if you desire blue blooms. Avoid high-phosphorus fertilizers, as phosphorus can hinder blue color development.

Fertilizing Hydrangeas to Encourage Blooming

Hydrangeas benefit from regular fertilization, but it’s crucial not to over-fertilize, which can lead to excessive foliage growth at the expense of flowers.

When to Fertilize: Fertilize in early spring as new growth emerges, and again in late spring or early summer. Avoid fertilizing in late summer or fall, as this can encourage new growth that is susceptible to frost damage.
Type of Fertilizer: Use a balanced 10-10-10 fertilizer or a fertilizer specifically formulated for flowering shrubs. For bigleaf hydrangeas and blue blooms, use an acid-loving plant fertilizer.
Fertilizer Application: Follow the fertilizer package instructions for application rates. Water the soil thoroughly after fertilizing to help distribute the nutrients and prevent root burn.
Avoid Over-fertilizing: Over-fertilizing, especially with high-nitrogen fertilizers, can result in lush green foliage but fewer flowers. If your soil is already rich in nutrients, you may not need to fertilize at all.

Pruning Hydrangeas for Shape and Bloom Production

Pruning hydrangeas correctly is essential for maintaining their shape, size, and encouraging abundant blooms. However, pruning times vary depending on the hydrangea species, as some bloom on old wood and others on new wood.

Pruning Hydrangeas that Bloom on Old Wood (Bigleaf, Lacecap, Mophead, Oakleaf)

When to Prune: Prune these types of hydrangeas immediately after they finish blooming in the summer, but no later than late summer. They set their flower buds for the next year on “old wood” (previous year’s growth) in late summer and fall.
How to Prune: Focus on removing dead, damaged, or crossing branches. You can also lightly shape the shrub. Avoid heavy pruning or pruning in the fall or spring, as this will remove the flower buds and reduce or eliminate blooms for the following season. For revitalization of overgrown shrubs (older than five years), you can remove up to one-third of the oldest stems at the base after blooming.

Pruning Hydrangeas that Bloom on New Wood (Smooth, Panicle)

When to Prune: Prune these hydrangeas in late winter or early spring before new growth begins. They bloom on “new wood” (current year’s growth).
How to Prune: You can prune these types more heavily. For smooth hydrangeas (like ‘Annabelle’), you can cut them back to the ground each year to encourage vigorous new growth and larger blooms (though this might result in weaker stems that need staking). For panicle hydrangeas (like ‘Limelight’ or ‘PeeGee’), you can prune back by about one-third to shape them and encourage larger flower heads. You can also train panicle hydrangeas into tree forms by pruning them to a single trunk.

:max_bytes(150000):strip_icc()/summer-blooming-oakleaf-hydrangeas-2132724-09-128eb6d70f844a0c8f8eb984bea6c6d7.jpg)

Propagating Hydrangeas to Expand Your Garden

Propagating hydrangeas is a rewarding way to create more of these beautiful shrubs for your garden or to share with friends. Stem cuttings are the most common and effective method.

Propagation by Stem Cuttings

Take Cuttings: In early fall, select healthy, non-flowering stems of new growth, about 6-8 inches long. Cut just below a leaf node using clean, sharp pruners.
Prepare Cuttings: Remove the lower leaves, leaving only the top set. Cut the remaining leaves in half horizontally to reduce moisture loss.
Rooting Hormone (Optional): Dip the cut end of the stem in rooting hormone powder or liquid to encourage faster root development.
Plant Cuttings: Insert the cuttings into pots filled with damp potting mix. You can place several cuttings in one pot.
Create Humidity: Cover the pot with a clear plastic bag to create a humid environment, making a few slits for air circulation. Ensure the plastic doesn’t touch the leaves.
Location and Care: Place the pot in a location with indirect light and keep the soil consistently moist but not waterlogged.
Transplanting: In 2-4 weeks, gently check for root development. Once rooted, transplant each cutting into its own pot to grow over winter before planting outdoors in the spring.

Propagation by Layering (Rooting Branches in Soil)

Select a Branch: Choose a low-growing, flexible branch that can be easily bent to the ground.
Prepare the Branch: Remove leaves from the section of the branch that will be buried.
Bury the Branch: Bend the branch to the ground and bury a portion of it (a few inches deep) in the soil. Secure it in place with a rock or brick.
Water and Wait: Keep the soil moist. Over time, roots will form at the buried node.
Separate: After several months or by the following growing season, check for root development by gently tugging on the branch. Once rooted, carefully sever the new plant from the parent shrub and transplant it to its desired location.

Potting and Repotting Hydrangeas in Containers

Hydrangeas can thrive in containers, especially compact varieties. Container gardening allows for greater control over soil conditions and the ability to move plants to protected locations during harsh weather.

Choosing a Pot: Select a large pot (16-24 inches in diameter) with good drainage holes. Avoid terracotta or ceramic pots that can crack in freezing temperatures.
Potting Mix: Use a high-quality potting mix amended with compost for good drainage and nutrient retention.
Sunlight and Watering: Potted hydrangeas need at least 4 hours of morning sun and regular watering as they tend to dry out more quickly than in-ground plants.
Repotting: Repot every 3-5 years as the hydrangea outgrows its container. Repot in early spring, moving to a slightly larger pot size.

Overwintering Hydrangeas in Colder Climates

Protecting hydrangeas during winter is crucial, especially for bigleaf hydrangeas, which are prone to bud damage from cold temperatures.

Mulching: Apply a thick layer of mulch around the base of the plant in late fall to insulate the roots and conserve soil moisture.
Wrapping: For bigleaf hydrangeas, wrap the plant in burlap to protect the flower buds from winter damage. Tie branches together gently before wrapping.
Potted Hydrangeas: Move potted hydrangeas to a sheltered location like a garage or unheated shed for the winter. Water sparingly during dormancy, just enough to keep the soil from completely drying out.

Troubleshooting Common Hydrangea Problems

Hydrangeas are generally resilient, but they can encounter certain problems.

No Blooms: Lack of blooms can be due to improper pruning (especially for old-wood bloomers), bud damage from late frosts, insufficient sunlight, over-fertilization (especially with high nitrogen), or drought stress.
Curling or Drooping Leaves: Leaf curl or drooping can be a natural response to heat, as hydrangeas conserve moisture. Check in the evening; if leaves revive, they are just heat stressed. If not, the plant may need watering. Persistent wilting could indicate root problems.
Yellowing Leaves: Yellow leaves can be caused by overwatering, underwatering, nutrient deficiencies, or viral issues. Check soil moisture and drainage.
Brown Leaves, Edges, or Tips: Brown edges or tips can result from fertilizer burn, salt buildup in the soil, or insufficient watering. Flush the soil with water to remove excess salts and adjust watering practices.
Pests and Diseases: Hydrangeas can be affected by aphids, spider mites, Japanese beetles, and diseases like powdery mildew and botrytis blight. Monitor plants regularly and address issues promptly with appropriate organic or chemical controls if necessary.

By following these comprehensive guidelines on planting and caring for hydrangeas, you can enjoy their stunning blooms and add lasting beauty to your garden for years to come.