Sorbus harrowniana Seeds | Harrow’s Rowan
LATIN NAME: Sorbus harrowniana
COMMON NAME: Harrow’s Rowan
Plant Profile
Sorbus harrowiana is a rowan of the mountains of south-west China, a small tree of six to ten metres with pinnate leaves of paired, serrated leaflets and flat heads of white flowers in late spring. It grows in scrub and forest edges in Yunnan and Sichuan, often on rocky ground above 2,000 metres.
The fruit ripens in late summer and is taken by birds within days, which is why the tree is grown more for its foliage and its autumn leaf colour than for the berries. The bark is smooth and grey, and the crown is upright when young, spreading with age.
Science & Biotechnology
The rowans are a complex group in which hybridisation and apomixis blur the species boundaries, and the Chinese taxa are particularly confused. Many plants in cultivation under names like this one are of uncertain origin, and the genus is currently being revised using genetic markers rather than leaf shape alone.
Rowans are bird-dispersed, and the fruit is eaten by thrushes and waxwings that pass the seed intact. The seed has a hard coat and a dormant embryo, so it germinates in the second or third spring after sowing, often after a cold winter followed by a warm spell. The tree is also used in shelterbelts on exposed hillsides, where its tolerance of wind and poor soil matters more than its fruit. The fruit is taken by birds so quickly that a tree can be stripped in two days, which is worth knowing if the berries are the reason for planting it.
Uses & Benefits
The tree is grown as an ornamental, for the white flower heads, the pinnate foliage and the yellow autumn colour. The wood is hard and pale and is used for tool handles and for turnery in its native range.
The fruit of most rowans is edible after cooking but bitter, and it is used for jelly in Europe; the Chinese species are rarely collected. In the garden the tree is best planted where the autumn colour can be seen against a dark background, and where the birds have somewhere to retreat to after stripping the fruit.
Growing from Seed
Seed needs warm then cold treatment: three months at 20°C, then three at 2 to 5°C, and germination in spring. Sowing fresh in autumn and leaving the pots outdoors for two winters also works, and the seedlings are then ready to prick out.
Plants want deep, moist but drained soil and sun or light shade, and they tolerate wind better than most rowans. They are best planted small, since the roots are sparse and resent disturbance. Stake for two years, mulch with leaf mould, and prune only to remove dead or crossing wood in winter. The tree is also tolerant of exposed sites once established, though the flowers are damaged by late frost in a cold spring.
Our Take
A mountain rowan for a cool, windy site, grown for its foliage and autumn colour rather than for fruit the birds will take first.
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