Rubus alumnus Plant Care

Rubus alumnus (Rubus alumnus) belongs to the Rosaceae family within the Rubus genus. Rubus alumnus is native to eastern and central Canada and the eastern and central United States.

Rubus alumnus displays a spreading, thicket-forming shrub growth habit, reaching up to 4 ft tall with a spread of approximately 6 ft. Rubus alumnus produces white or pink five-petaled flowers in clusters.

Leaf size: approximately 4 inches.

Water a young or newly planted Rubus alumnus every 3–5 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Rubus alumnus thrives in full sun to partial shade.

Rubus alumnus tolerates temperatures of 50–80°F. Rubus alumnus prefers humidity levels of 40–70%.

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

Feed Rubus alumnus every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs 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.

Rubus alumnus is suited to USDA Zone 4a – 8b.

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

Rubus alumnus can spread to about 6 ft (1.8 m) and reach about 4 ft (1 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 plant spacing calculator.

Prune Rubus alumnus 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 shrub in one year.

Rubus alumnus is hardy down to USDA zone 4a, so once established it can stay outdoors through winter in that zone and warmer ones.

Water deeply in late autumn before the ground freezes, and spread a 5–8 cm (2–3 in) layer of mulch over the root zone, keeping it away from the trunk.

Young and container-grown shrubs need extra protection: roots in a pot freeze much more easily than roots in the ground.

Rubus alumnus can be propagated through division, stem cuttings, layering. Similar propagation techniques also apply to black raspberry plant care, which shares the same genus.

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

Rubus alumnus is susceptible to aphids, spider mites, raspberry fruitworm. 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.

Rubus alumnus grows outdoors in USDA Zone 4a – 8b. It survives winters down to planting zone 4a. Rubus alumnus is native to eastern and central Canada and the eastern and central United States.