Photo: Eeno11 — CC BY-SA 3.0 · source
Survives zone 3 through 7
Harvest calendar
Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.
Rowan — also called mountain ash — is famous for berries that are far too astringent and acidic to eat raw in any quantity; British tradition instead cooks them, often after a frost or a spell in the freezer to break down the bitter parasorbic acid, into the classic tart preserve rowan jelly, along with compotes, chutneys and syrups.
- Hardiness
- Zone 3–7
- Habit
- Tree
- Edible part
- Fruit
- Ripens
- Summer–autumn
- Mature size
- Tree 8–15 m, upright and open-crowned
- Light
- Full sun to partial
- Soil pH
- 6.0–7.0 (near-neutral)
- Environment
- Temperate to boreal
- Native range
- Most of Europe — from Iceland and the British Isles to Spain, the Balkans (Macedonia) and the Caucasus — extending across temperate Asia through Russia to northern China and Korea; notably absent from Japan.
- Status
- Both wild and cultivated
- Years to fruit
- 2–4 yrs
- Growth speed
- Medium growth rate, reaching about 10-15 m tall by 7 m spread at a medium pace once established.
- Spacing
- 500 cm (197 in) apart — about 25 m² (269 sq ft) per plant
- Leaf shape
- Pinnately compound, rowan-type leaves with 4-9 pairs of toothed leaflets plus a terminal leaflet, each leaflet 2-6 cm long.
- Root system
- A branching 'heart root' — several primary roots divide from the crown and grow down and outward rather than forming a single taproot.
- Fruit description
- Small round pomes 7.5-10 mm across, ripening from green through orange to scarlet with a persistent black five-pointed calyx at the base. The raw fruit is very acid and bitter — high in parasorbic acid — and can upset the stomach if eaten raw in quantity; cooking or a hard frost breaks down the bitterness, after which the berries are traditionally made into rowan jelly, jam, compote, chutney or a tart syrup, or dried and ground into a flour mixed with cereals.
- Propagation
- By seed — sow fresh in a cold frame, or give stored seed 2 weeks warm followed by 14-16 weeks cold stratification and sow as early in the year as possible; germination is often slow and erratic, and seedlings grow slowly above ground for their first year or two while establishing roots. Ornamental and fruiting cultivars are propagated by grafting onto seedling rowan or whitebeam rootstock.
- Pollination
- Self-fertile
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.
Growing guide
Fertilizing. Not a heavy feeder — thrives in nutritionally poor, sandy, loamy or clay soils provided drainage is adequate, and prefers a cool, moist, neutral-to-slightly-acid soil; it dislikes shallow, drought-prone ground. A light annual mulch is more beneficial than fertilizer; avoid excess nitrogen, which promotes soft growth vulnerable to fireblight.
How it spreads. A standard tree with a single, non-suckering trunk that spreads only by seed — birds that eat the berries are the primary means of dispersal, and rowan often acts as an early pioneer species colonizing disturbed or open ground from seed rather than by vegetative spread.
Growing tips. Hardy to USDA zones 3-7 (UK zone 2) and extremely wind-firm, tolerating very exposed, maritime and polluted sites; fruits best in full sun. Susceptible to fireblight, and also affected by rust fungi that cause leaf galls and by various sawflies and other insect pests. Its tolerance of poor soils and exposure makes it a common pioneer and amenity tree on marginal ground.
Grow journal
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