At Dunedin Botanic Garden there is a compact species of rowan that is even more intrepid, Sorbus reducta.
A native of west China and Myanmar, it grows on rocky mountain slopes at altitudes of between 2200 and 4000m.
However, the price it pays for venturing beyond the treeline is a drastic reduction in stature.
Whereas the common rowan tree will grow up to 15m tall, the compact Sorbus reducta grows to only about 1m in the harsh conditions of the higher terrain.
So rather than a tree, S. reducta is a dwarf shrub that, in good moist soil, will gradually spread by short suckers to become a clump about 1m wide.
Like its European relative, Sorbus reducta has nine to 15 leaflets per leaf which, at this time of year, are changing from dark green to bronze, red-purple.
Like other sorbus, it is quite understated in bloom, but its clusters of small, off-white flowers develop in autumn, into attractive pink berries that stand out against the leaves and can last well after the leaves have finally dropped.
As well as a specimen in the Rhododendron Dell's peat garden, there are three in the rock garden, all of them demonstrating just how well this little sorbus suits small spaces.
- Doug Thomson is curator of the Rhododendron Dell at Dunedin Botanic Garden.
