How Tall Do Hydrangeas Get?

Hydrangeas (Hydrangea spp.) are among the most popular deciduous garden shrubs, prized for their large blooms, dramatic leaves and, depending on species, fall color. Growth rates and mature sizes of hydrangeas vary widely, depending on species, variety and growing conditions. Some are compact enough to be grown successfully in large containers. Modern breeders have worked with traditional favorite types to create newer varieties that combine the large flower heads typical of hydrangeas with manageable sizes that work better in small spaces.

Bigleaf hydrangea (Hydrangea macrophylla), hardy in U.S. Department of Agriculture plant hardiness zones 6 through 9, is the familiar "mophead" type found in many landscapes, with pink, blue or purple flowers. It grows fast, up to 25 inches per year, reaching an ultimate height of 6 feet or more, with an equal spread. Smaller, dwarf varieties, like "Pia" (Hydrangea macrophylla "Pia"), hardy in USDA zones 5 through 9, can be half that size, growing 2 to 3 feet tall and wide.

Panicle hydrangea (Hydrangea paniculata), hardy in USDA zones 3 through 8, is often larger in size than bigleaf varieties. Though the mature size can vary greatly, the shrubs normally grow between 10 and 20 feet in height, with a similar spread. The conical white flowers are 6 to 8 inches long. These hydrangeas also grow up to 25 inches per year. Compact forms, like Pinky-Winky (Hydrangea paniculata "Dvppinky" Pinky-Winky), also hardy in USDA zones 3 thorugh 8, are smaller. Pinky-Winky, grows 6 to 8 feet tall and 5 to 6 feet wide. The flower panicles may be 12 inches long.

Oakleaf hydrangea (Hydrangea quercifolia) is usually somewhat shorter than the panicle varieties and about the same height as standard bigleaf varieties. Hardy in USDA zones 5 through 9, it grows 4 to 6, or even 8, feet tall and sometimes even wider, as the shrubs have a suckering habit. The growth rate is slow to medium, between 12 and 24 inches per year. Compact forms, like little "PeeWee" (Hydrangea quercifolia "PeeWee"), hardy in USDA zones 5 through 9, grow only 3 to 4 feet tall and 2 to 3 feet wide. Dwarf and standard varieties bear conical flower heads.

To maximize the height of any hydrangea, plant young shrubs in rich, well-drained soil that's consistently moist. Mulch with 2 inches of organic material in a 2-foot radius around the base of each plant to help conserve soil moisture, and supplement by watering during dry spells. The plants prefer light shade and will withstand direct sunlight only when they have plenty of water. Fertilize every three months with a granular flowering shrub product, like 18-6-12, applied at the rate of 1/4 cup per plant, sprinkled around the base of each plant. Water thoroughly immediately after fertilizing.