Mountain Hydrangea Plant Care

Mountain Hydrangea (Hydrangea serrata) belongs to the Hydrangeaceae family within the Hydrangea genus. Mountain Hydrangea is native to mountainous regions of Korea and Japan. Mountain Hydrangea is also known as Tea of Heaven.

Mountain Hydrangea displays a deciduous shrub, mounding habit growth habit, reaching up to 6 ft tall with a spread of approximately 6 ft. Mountain Hydrangea produces large, showy clusters of pink, blue, purple, or white flowers.

Leaf size: approximately 6 inches.

Water a young or newly planted Mountain Hydrangea every 3–7 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Mountain Hydrangea thrives in partial shade to filtered sun. Avoid placing Mountain Hydrangea in direct, harsh sunlight for extended periods, as this can scorch the foliage.

Hydrangea serrata tolerates temperatures of 60–75°F. Mountain Hydrangea prefers humidity levels of 40–70%.

Rich, moist, well-draining soil with plenty of organic matter. Good drainage is essential for Mountain Hydrangea to prevent waterlogging, which leads to root rot and fungal issues.

Feed Mountain Hydrangea every 4 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Choose a spot with partial shade to filtered sun and rich, moist, well-draining soil with plenty of organic matter. Avoid low spots where water collects after rain.

Mountain Hydrangea is suited to USDA Zone 13a.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

Mountain Hydrangea can spread to about 6 ft (1.8 m) and reach about 6 ft (2 m) tall. Space plants about 6 ft (1.8 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

Prune Mountain Hydrangea while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

Mountain Hydrangea is frost-tender (hardy to USDA zone 13). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Mountain Hydrangea can be propagated through softwood cuttings, layering, division. Similar propagation techniques also apply to hydrangea plant care, which shares the same genus.

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Mountain Hydrangea is susceptible to aphids, spider mites, scale insects. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

Mountain Hydrangea grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Mountain Hydrangea is native to mountainous regions of Korea and Japan. In cooler regions, grow Mountain Hydrangea as a houseplant or bring it indoors before the first frost.