Quassia Plant Care

Quassia (Picrasma quassioides) belongs to the Simaroubaceae family within the Picrasma genus. Quassia is native to temperate regions of southern Asia, from the northeast of Pakistan east along the Himalaya and through East Asia from southern, central and eastern China to Taiwan, Japan and Korea. Quassia is also known as Bitterwood.

Quassia displays a small to medium-sized tree growth habit, reaching up to 20 ft tall with a spread of approximately 15 ft. Quassia produces small clusters of greenish-yellow flowers.

Leaf size: approximately 6 inches.

Water a young or newly planted Quassia 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.

Quassia thrives in full sun to partial shade.

Picrasma quassioides tolerates temperatures of 60–85°F. Quassia prefers humidity levels of 40–70%.

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

Feed Quassia every 6 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.

Quassia 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.

Quassia can spread to about 15 ft (4.6 m) and reach about 20 ft (6 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 Quassia 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.

Quassia 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.

Quassia can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to picrasma crenata plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Quassia is susceptible to aphids, 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.

Quassia grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Quassia is native to temperate regions of southern Asia, from the northeast of Pakistan east along the Himalaya and through East Asia from southern, central and eastern China to Taiwan, Japan and Korea. In cooler regions, grow Quassia as a houseplant or bring it indoors before the first frost.