The best garden plants are ones that look great for more than just the few weeks that they’re at their peak. While many summer-blooming perennials put on a lovely show during the warmer months, it’s unusual to find a plant that looks just as good in the cool autumn months. Fortunately, oakleaf hydrangeas earn their keep for many months of the year.
Unlike standard hydrangea bushes that put on their best show with large blooms in early summer but fade by the end of August, oakleaf hydrangeas add a second round of color to your landscape when their leaves turn from green to red, bronze and purple as temperatures drop.
Oakleaf Hydrangea Basics
Growing Zones: 5-9
Bloom Time: Flowers in early summer; colorful leaves in autumn
Exposure: Full sun to part shade
Mature Size: Up to 15 feet tall and 15 feet in diameter, but many smaller varieties are available
Notes: Oakleaf hydrangeas form a shrub with arching branches that support large panicles of flowers in shades of white, pink or purple. Long-lasting flowers can dry in place on branches for an attractive look that lasts for months. Green, leathery leaves are shaped like oak leaves and turn red, purple or bronze in autumn. Some varieties feature attractive peeling bark on branches for winter interest.
Growing Oakleaf Hydrangeas in the Landscape
Oakleaf hydrangeas can be planted alone as a specimen within a flower bed or foundation grouping, or you can plant them together as a hedge for major seasonal impact. Although they tolerate partial shade, their leaf color will be most intense when planted in full sun.
Planting Oakleaf Hydrangeas
To plant your oakleaf hydrangea, dig a hole twice as wide as the root ball of your plant and deep enough that you’ll be able to set the crown at the same depth it was in its container. Add compost to the hole to break up clay soil and provide good drainage. Place your plant in the hole and backfill with a 50/50 mixture of soil and compost, pressing the soil firmly over the root ball.
Water your plant deeply and add a layer of mulch to keep roots cool. Oakleaf hydrangeas need steady moisture until they get established, but in future seasons, these hardy natives are quite drought tolerant. In most areas, an inch of rain per week is ideal.
Ongoing Care for Oakleaf Hydrangeas
To encourage healthy growth, fertilize your oakleaf hydrangea each spring with a general-purpose garden fertilizer and top dress with fresh compost. Unlike mophead-style hydrangeas, oakleaf hydrangeas won’t change their flower color based on soil acidity, so there’s no need to monitor or alter the pH of your soil.
Because hydrangeas flower on old wood, it’s best to avoid pruning so you don’t accidentally remove flower buds and miss out on summer blooms. If you’re careful about reading the label for the mature size and not crowding the plants, you won’t need to prune unless there’s dead wood to remove after winter damage. To do this, wait until late spring to clip unproductive branches off near the base of the plant.
Oakleaf hydrangeas are occasionally bothered by aphids and Japanese beetles, which eat the plant’s leaves and can weaken its growth. To control them, pick them off by hand and drop them into a bucket of soapy water or spray the branches with an insecticidal soap or Neem. Once established, native oakleaf hydrangeas are usually well-adapted to a range of growing conditions and provide months of beauty to your landscape.