Cultivation

Most of the species Sorbus, such as S. pallescens, S. aria and

S. aucuparia, found in nurseries are grown from seed. All the named cultivars, however, are grafted. This is because there is no other way to replicate the authenticity of a particular cultivar that will not come true to form from seed. I plant my rowans and whitebeams as young as possible when they’re about 1-2m tall if grown from seed, and as a one-year old grafted maiden, just over 1m for the cultivars. Usually, these trees are container grown with young vigour and are generally quick to establish. With grafted specimens, the rootstocks will produce suckers that should be removed early in their growth by rubbing off the fresh green shoots with the thumb or, once they start to lignify, use secateurs before they get too woody. With seed-raised specimens, any shoots from the base can be retained and allowed to grow to form a multi-stemmed tree.

All Sorbus have a shallow root system and need a free-draining, acid to alkaline soil, but with some moisture, and will not tolerate their roots drying out. They prefer to be planted in cultivated ground, such as in a shrub or herbaceous border, where the roots zone is shaded, and they do not always approve of being planted as a single specimen in a lawn with fine turf where the tree roots cannot compete with compaction and constantly drying out.

I prefer to plant in groups of three or five where space permits as they lend themselves to companionship and look more natural in that setting. All Sorbus are subject to infection from a variety of pests and diseases, particularly fire blight ( Erwinia amylovora), and to avoid infection be sure to buy from nurseries that are free from the disease and ensure that all your pruning tools are cleaned and sterilised between pruning individual trees. When pruning, always remove branches back to a strong lateral growth.