Mountain Walnut Plant Care

Mountain Walnut (Cryptocarya ampla) belongs to the Lauraceae family within the Cryptocarya genus. Mountain Walnut is native to Central America, South America. Mountain Walnut is also known as Mountain Laurel.

Mountain Walnut displays a tall, evergreen tree growth habit, reaching up to 30 ft tall with a spread of approximately 15 ft. Mountain Walnut produces small, inconspicuous flowers.

Leaf size: approximately 6 inches.

Water a young or newly planted Mountain Walnut 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.

Mountain Walnut thrives in partial to full shade. The optimal light range is 100–500 lux. Avoid placing Mountain Walnut in direct, harsh sunlight for extended periods, as this can scorch the foliage.

Cryptocarya ampla tolerates temperatures of 50–80°F. Mountain Walnut prefers humidity levels of 60–80%. A pebble tray or humidifier helps maintain adequate moisture around the plant.

Well-draining, rich loamy soil with added organic matter. Good drainage is essential for Mountain Walnut to prevent waterlogging, which leads to root rot and fungal issues.

Feed Mountain Walnut 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 partial to full shade and well-draining, rich loamy soil with added organic matter. Avoid low spots where water collects after rain.

Mountain Walnut is suited to USDA Zone 10b – 12b.

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 Walnut can spread to about 15 ft (4.6 m) and reach about 30 ft (9 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 Mountain Walnut 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 Walnut is frost-tender (hardy to USDA zone 10). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

Mountain Walnut can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to peumo plant care, which shares the same genus.

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

Mountain Walnut is susceptible to scale insects, caterpillars. 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 Walnut grows outdoors in USDA Zone 10b – 12b. It survives winters down to planting zone 10b. Mountain Walnut is native to Central America, South America. In cooler regions, grow Mountain Walnut as a houseplant or bring it indoors before the first frost.