service tree

Photo: BotBln — CC BY-SA 3.0 · source

Survives zone 5 through 8

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Service tree bears the largest fruit in the genus — apple- or pear-shaped 'sorbs' that are hard and astringent when freshly picked and are traditionally bletted (stored until almost overripe) to become sweet and richly flavored, much like a medlar; in parts of France, especially Normandy and the historic Maine region, small amounts of tannin-rich sorb juice have long been blended into cider, and a dedicated sorb cider called cormé is still produced and celebrated there today. ⚠ Not just astringent: raw fruit in this group contains parasorbic acid, which causes vomiting, stomach cramps and diarrhoea if you eat any quantity of it. Cooking, freezing, drying or a hard frost converts it to harmless sorbic acid — which is exactly why every traditional recipe cooks it and why the fruit is picked after the first frosts.

Hardiness

Zone 5–8

Habit

Tree

Edible part

Fruit

Ripens

Summer–autumn

Mature size

Tree 10–20 m — the largest of the group, and long-lived with it

Light

Full sun to partial

Soil pH

6.0–7.0 (near-neutral)

Environment

Temperate

Native range

Southern and Central Europe, the Atlas Mountains of northwest Africa, northern Anatolia, and east to the Caucasus and northwestern Iran, with additional naturalized or planted populations in Britain, Turkey, Portugal and Cyprus.

Status

Both wild and cultivated

Years to fruit

2–4 yrs

Growth speed

Medium growth rate, around 20-40 cm per year, reaching 15-20 m tall by roughly 6-8 m spread over a very long lifespan.

Spacing

700 cm (276 in) apart — about 49 m² (527 sq ft) per plant

Leaf shape

Pinnately compound, rowan-type leaves 15-25 cm long with 13-21 toothed leaflets.

Root system

A branching 'heart root', with several primary roots dividing from the crown and running down and outward rather than forming one central taproot.

Fruit description

Large pomes 2-3 cm across, apple-shaped or pear-shaped depending on the form, greenish-brown often flushed red on the sun-exposed side. Fresh fruit is hard, gritty and strongly astringent — essentially inedible off the tree — and is traditionally bletted, left in a cool, dry place until almost, but not quite, going rotten, at which point it softens into something described as lusciously tropical in flavor; sorbs can also be dried and used like prunes, or pressed for their tannin-rich juice, a traditional addition to French cider (cormé).

Propagation

By seed — sow fresh in a cold frame as soon as ripe, or give stored seed 2 weeks warm followed by 14-16 weeks cold stratification; seedlings are very slow to put on top growth in their first year or two, spending that time building up a substantial root system instead. Named fruiting selections (grown for larger or better-flavored sorbs) are propagated by grafting.

Pollination

Only partially self-fertile — unlike the fully self-fertile rowan (S. aucuparia), service tree sets noticeably more fruit when cross-pollinated by insects from a second, genetically distinct tree.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.