How to Grow Hydrangeas

Lovely, old-fashioned hydrangeas, the mavens of the South, deserve a place in every garden. They have a reputation for being difficult to grow, but nothing could be further from the truth. The secret to growing hydrangeas is to choose a variety suited for your area and plant it in the right location. With proper care, hydrangeas will grace your garden with large blooms for 30 years or more.

Choosing Hydrangeas

French or Bigleaf Hydrangeas.

When people think of hydrangeas, they generally think of French or mophead hydrangeas (H. macrophylla). These plants produce rounded clusters of pink or blue blossoms. These are the plants you’ll find in decorative pots in the spring. They’re often sold as houseplants. Unfortunately, they’re hardy only to USDA plant hardiness zone 6 or 7. Acidic soils create blue flowers, while alkaline soils encourage pink blooms. Prune right after flowering.

Peegee hydrangea

(Hydrangea paniculata grandiflora). Hardy to zone 4, this plant grows quickly to 6 to 8 feet high. It produces globes of white flowers mid-summer when few other shrubs are blooming. Dry the flowers for winter arrangements. Peegee hydrangea blooms on new wood, so prune it back when it is dormant.

Smooth hydrangea

(Hydrangea arborescens). Also hardy to zone 4, this compact shrub grows 3 to 5 feet wide and produces white blooms most of the summer. Cut it back while dormant. It grows quickly and blooms on new wood. Try ‘Annabelle’ or ‘Grandiflora.’

Oak-leaf Hydrangea

(H. quercifolia). This old favorite produces slightly flattened white flowers through late summer, followed by gorgeous fall foliage. The plant is hardy only to zone 5, with winter protection. Oak-leaf hydrangea blooms on old wood, so prune it after flowering. Common varieties include ‘Snow Queen’ and ‘Alice.’

Climbing hydrangea

(Hydrangea anomala). This interesting vine grows 6 to 8 feet high, with peeling red bark. It takes a while to become established, but becomes a beautiful flowering vine. Give it plenty of support since the woody trunk becomes heavy. Hardy in zones 4 through 7.

Caring for Hydrangeas

Hydrangeas have big leaves and produce extravagant flowers. Consequently, they need plenty of moisture and nutrients to support this growth. Native hydrangeas grow in woodland areas. Try to simulate these growing conditions for best results.

Choose a location that gets dappled sunlight in the morning and some afternoon shade. In hot climates, afternoon shade is absolutely critical to your growing success. A site with eastern or northern exposure is best. Amend the soil with compost, manure and peat moss to improve drainage and add nutrients.

Water hydrangeas frequently, especially in the first year after planting, to keep the soil evenly moist, but not soggy. Plant hydrangeas so air circulates freely since these plants are prone to some fungal diseases. Use drip systems instead of overhead sprinklers to keep the leaves dry.

Fertilize hydrangeas with an all-purpose fertilizer in early spring when new growth appears and again, mid-summer. Don’t fertilize them in late summer, though, which encourages new growth that will be winter-killed.

When and how to prune hydrangeas is often a source of confusion, but it doesn’t have to be. Prune hydrangeas that bloom on new wood, such as PeeGee hydrangeas, any time from late fall to early spring (while they are dormant). These plants grow quickly and benefit from a hard pruning. In some cases, you can prune them all the way back to the ground.

Take a more conservative approach with French and Oak-leaf hydrangeas. These plants bloom on old wood. Prune them in late summer after they’ve bloomed to remove old dead wood or branches that rub against each other.

Using Hydrangea Blooms

Hydrangeas make beautiful cut flower arrangements. Place a few stems in a vase or combine them with roses, peonies or similar flowers. To dry hydrangeas, simply cut the stems in the fall when the flowers have started to dry slightly. Place them in a cool, dry location out of sunlight and allow them to dry completely.

To learn more about how to grow hydrangeas, check out these pages:

Pruning Hydrangeas from Fine Gardening

Hydrangea from Clemson University

By Julie Christensen
When she’s not writing about gardening, food and canning, Julie Christensen enjoys spending time in her gardens, which includes perennials, vegetables and fruit trees. She’s written hundreds of gardening articles for the Gardening Channel, Garden Guides and San Francisco Gate, as well as several e-books.