Viburnum trilobum – American Highbush Cranberry seeds

Description

Viburnum trilobum, commonly known as American cranberrybush, is a cold-hardy, deciduous shrub native to North America. It produces clusters of bright red, cranberry-like fruit in autumn, high in vitamin C and suitable for preserves, jellies, and sauces once cooked. The shrub also features attractive white lace-cap flowers in spring and brilliant red foliage in autumn, making it valuable both ornamentally and as a food plant.

It typically grows 2–4 metres tall and wide, forming a dense, rounded shape. It prefers full sun to part shade and tolerates a range of soils, including moist or poorly drained sites. V. trilobum is well-suited to temperate parts of New Zealand and thrives with regular watering during dry spells. It’s highly cold-tolerant, hardy down to –40°C.

This species is self-fertile to a degree, but cross-pollination between genetically distinct individuals improves fruit yield and quality. If growing from seed, plant at least three to five seedlings to ensure adequate genetic diversity and consistent cropping.

Germination and Cold Stratification:
Seeds of Viburnum trilobum have a natural dormancy that takes time to overcome. They require a warm moist period (20–25°C) of about 3 months, followed by a cold moist stratification (1–5°C) for another 3–4 months. This mimics their natural cycle. Germination may occur in late spring of the second year.

Outdoor Stratification Tip:
In cold regions of New Zealand, Viburnum trilobum seeds can be sown into moist trays or pots and left outdoors over winter. To improve success, begin with a warm phase indoors (about 3 months), then move the seeds outside for natural chilling. Be sure to protect them from rodents. Germination will likely occur the following spring or later.