White Ash Plant Care

White Ash (Alphitonia petriei) belongs to the Rhamnaceae family within the Alphitonia genus. White Ash is also known as Red Ash.

White Ash displays a small to medium-sized tree growth habit, reaching up to 25 ft tall with a spread of approximately 15 ft. White Ash produces small clusters of white or cream-colored flowers.

Leaf size: approximately 4 inches.

Water a young or newly planted White Ash every 7–14 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.

White Ash thrives in full sun to partial shade.

Alphitonia petriei tolerates temperatures of 50–85°F. White Ash prefers humidity levels of 40–70%.

Well-draining loamy soil with added compost for nutrients. Good drainage is essential for White Ash to prevent waterlogging, which leads to root rot and fungal issues.

Feed White Ash every 8 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 full sun to partial shade and well-draining loamy soil with added compost for nutrients. Avoid low spots where water collects after rain.

White Ash is suited to USDA Zone 12a.

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.

White Ash can spread to about 15 ft (4.6 m) and reach about 25 ft (8 m) tall. Space plants about 15 ft (4.6 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 White Ash 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.

White Ash is frost-tender (hardy to USDA zone 12). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

White Ash can be propagated through seeds, hardwood cuttings. Similar propagation techniques also apply to red ash plant care, which shares the same genus.

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White Ash is susceptible to aphids, scale insects, leaf miners. 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.

White Ash grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow White Ash as a houseplant or bring it indoors before the first frost.