River birch

Sun

Full sun to partial shade; the best growth and crown development occur in full sun.

Water

Prefers consistently moist soil and tolerates periodic flooding. Established trees tolerate some dry spells, but prolonged drought can cause leaf drop.

Soil

Moist, acidic soil rich in organic matter; clay, loam and sandy soils are suitable if moisture is available. Alkaline soil often causes iron chlorosis.

Height

40-70 ft (12-21 m)

Spread

40-60 ft (12-18 m)

Flowers

Spring: yellow-brown male catkins and small green female catkins, usually before or as the leaves emerge.

Foliage

Diamond-shaped to oval green leaves with pointed tips, doubly toothed edges and paler undersides; usually yellow in autumn.

Growth

Fast when young, especially in moist soil.

Care needed

Medium

• Water deeply through dry weather during the first two or three growing seasons, keeping the root ball moist but not permanently waterlogged.
• Apply a 2-3 in (5-8 cm) layer of organic mulch over the root zone, leaving the trunk bases clear.
• Check soil pH before planting; choose another tree if the soil is strongly alkaline.
• Do not feed routinely; use soil-test results to guide any fertilizer application.
• Stake only if the root ball moves in wind, and remove supports after the first growing season.
• Allow room for the broad crown and shallow roots; avoid planting close to paving or where lawn irrigation cannot reach.

Pruning. Prune lightly in late summer to remove crossing branches and establish sound branch structure; remove dead or dangerous wood whenever necessary. Avoid heavy pruning and routine late-winter or spring cuts, which can bleed sap.

Spring

Plant while conditions are cool and the soil is workable; water thoroughly and mulch.

Late spring

Check new foliage for yellowing between green veins; test soil pH before treating suspected iron deficiency.

Summer

Water during extended dry spells, especially for young trees; check moisture beneath the mulch.

Late summer

Carry out any necessary light structural pruning, avoiding heavy canopy removal.

Autumn

Replenish mulch and water newly planted trees if rainfall is low.

Winter

Inspect trunks and branch unions for damage, and check that tree ties are not rubbing or constricting the bark.

• Use as a specimen on an open lawn where the peeling bark and spreading crown can be seen.
• Plant in loose groups beside a pond or drainage swale, allowing space for mature crowns.
• Combine with moisture-loving shrubs and ferns in a woodland garden.
• Place against dark evergreen foliage to highlight the pale, peeling bark in winter.

Garden styles it suits: Woodland, Wildlife garden, Winter interest, Bog garden, Modern rustic and Grand estate.

Plant it with: Winterberry, Red-twig dogwood, Virginia sweetspire, Royal fern, Astilbe and Soft rush.

Wildlife: Supports caterpillars and other insects eaten by birds. Small seeds feed birds, and the branching canopy provides nesting and shelter.

• Iron chlorosis: leaves turn yellow between green veins on alkaline soil. Confirm with a soil test; seek advice on iron treatment, and consider replacement if the site is persistently unsuitable.
• Drought stress: leaves yellow or drop early in hot, dry weather. Water deeply and maintain mulch over the root zone.
• Aphids: curled leaves and sticky honeydew may occur. Small infestations usually need no treatment; encourage predators and rinse reachable foliage with water.
• Leaf spots: fungal spotting can develop in humid weather. Collect fallen leaves, avoid wetting foliage and maintain airflow; established trees rarely need fungicide.

Not known to be toxic to cats, dogs, horses or people. No part is recognized as a serious poisoning hazard, though it is not a food plant; windborne pollen can trigger allergies.

• Paper birch (Betula papyrifera)

  Mature bark is usually chalky white and peels in broad, papery sheets, rather than the salmon-to-cinnamon curls typical of river birch.

• Silver birch (Betula pendula)

  Usually has white bark with black fissures near the base and slender, drooping branchlets; river birch has warmer-coloured peeling bark and generally broader leaves.

• Sweet birch (Betula lenta)

  Also called black birch, but its young bark is dark and relatively smooth rather than curling into papery flakes; scratched twigs smell of wintergreen.

Betula is the Latin name for birch, nigra means black, and river birch refers to its natural habitat along streams and floodplains.

Propagation. Sow fresh seed promptly after it ripens in late spring or early summer; press it onto moist seed compost without burying it deeply. Named cultivars need vegetative propagation, usually softwood cuttings under mist, to retain their characteristics.

Accepted botanical name

Betula nigra

In the US and Canada

Native in the lower 48 states.

Native range

Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas and Kentucky.

Measured

Soil pH 3 to 6.5. Average height 2438 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.