Sorbus domestica Seeds | Service Tree
LATIN NAME: Sorbus domestica
COMMON NAME: Service Tree
Plant Profile
Sorbus domestica is a sturdy tree of warm lowlands, reaching 15 m or more, with pinnate leaves of up to 20 leaflets that give it an ash-like look until the fruit appears. The white, five-petalled flowers open in flat-topped clusters in late spring and are worked by bees and flies. The fruit is a small pome, 2 to 3 cm across, green then russet, with one to five seeds in hard, cartilaginous coats.
In Britain the true service tree is a rarity, known from a handful of old sites in the south and west, and it is treated as near-threatened there and scarce across the northern edge of its range. Its slow growth, unreliable cropping and the loss of old orchards have all worked against it, and many surviving trees are old individuals in hedges rather than planted stock.
The service tree stands apart from the whitebeams and rowans that make the genus Sorbus so difficult. It is a diploid, and molecular work places it in a lineage of its own, so several authorities now treat it as Cormus domestica. That separation matters practically: the tree does not hybridise freely with the rowans the way the whitebeam complex does.
Service wood is hard, heavy, fine-textured and pale, with a pinkish tinge in the heart, and it was once in demand for exactly the jobs that punish a softer timber. Mill cogs, screws, tool handles, plane bodies and joinery all took it, and the wood works cleanly and holds a thread well. It is also prized by turners, and a mature tree yields a considerable volume of it. Give the tree deep, warm soil and full sun, and keep the mower well away from the trunk.
Science & Biotechnology
Sorbitol, the sugar alcohol now used in food and pharmaceuticals, was first isolated from the berries of a Sorbus species, and it takes the genus name. The compound occurs in many rosaceous fruits, and its discovery in this genus is why the chemical carries a botanical name rather than a descriptive one.
The clarifying action in the cider vat is the work of procyanidins, the condensed tannins that give both service fruit and cider apple their astringency. They bind proteins and pectin residues, dropping them out of suspension, and they protect the finished drink from spoilage by binding the enzymes that would otherwise turn it brown.
Uses & Benefits
Service fruits are not eaten fresh. They are bletted: spread out and left until the flesh darkens, softens and sweetens as the cell walls break down and the tannins fall. Bletted fruit is eaten with cheese, but the tree’s real commercial niche is drink. In Hesse, service fruits are added to apple must before fermentation, where their tannin clarifies the cloudy juice and gives the finished cider backbone and keeping quality.
Growing from Seed
Because the two fruit forms breed true only by vegetative means, named stock is grafted. Rowan and whitebeam seedlings serve as rootstock, and the scion is worked on in late winter. A grafted tree crops earlier than a seedling and keeps the fruit shape you chose.
Wash the seeds out of bletted fruit and sow them in a gritty loam, 1 cm deep, in a deep pan. The seed coat is hard and the embryo slow, so the seed usually wants a warm, moist spell followed by a cold one, and a proportion of any batch will hold over for another year. Pot the seedlings on when they show two true leaves and grow them in a nursery row at 30 cm until they stand 60 cm.
Plan for the delay rather than fighting it. Keep the pan outdoors, protected from mice, and leave it alone; seed that has not come up by the end of the first spring is often waiting for the second. Fresh seed sown straight from bletted fruit is the most reliable route. Label every pan, because the two fruit forms are worth keeping apart and a mixed batch is easy to muddle when the seedlings are small.
Our Take
Plant a service tree for your grandchildren and enjoy the blossom while you wait. Anyone interested in the genus should look at the whitebeam for chalk soils and at the Swedish whitebeam for a tougher, smaller tree, while Sitka mountain-ash is the one to grow if you want fruit for the birds.
Related Reading
Gardeners who grow Service Tree often pair it with these related subjects: