Black gum

Sun

Full sun to partial shade; autumn colour is usually strongest in full sun.

Water

Moderate to high; prefers consistently moist soil and tolerates occasional flooding. Established trees tolerate short dry spells, but prolonged drought can cause leaf scorch and early leaf fall.

Soil

Acidic, humus-rich soil, preferably moist but well drained. Tolerates clay; avoid chalky or strongly alkaline soil.

Height

30-50 ft (9-15 m), occasionally taller

Spread

20-30 ft (6-9 m)

Flowers

Small, inconspicuous greenish-white flowers in late spring.

Foliage

Alternate, oval, glossy dark green leaves with mostly smooth edges; yellow, orange, scarlet or purple in autumn.

Growth

Slow to moderate

Care needed

Low

• Plant a young, container-grown tree in its permanent position; established trees are difficult to transplant.
• Keep the root flare at soil level and water deeply through the first two or three growing seasons.
• Spread 2-3 in (5-8 cm) of organic mulch over the root area, keeping it clear of the trunk.
• Water during prolonged dry weather, especially on sandy soil.
• Avoid routine feeding; use a soil test before adding fertiliser or attempting to correct soil acidity.

Pruning. Prune in late winter while dormant, removing dead, damaged or crossing branches. Establish a sound central leader while young, then keep pruning light and never top the tree.

Late winter

Check branch structure and remove damaged or crossing growth before buds open.

Spring

Plant container-grown trees when the soil is workable, then water thoroughly.

Late spring

Refresh mulch without covering the root flare; check new leaves for yellowing between green veins.

Summer

Water young trees deeply during dry spells and keep grass away from the trunk.

Autumn

Collect ripe fruit if raising trees from seed; clean off the flesh before sowing.

Late autumn

Check young trees for rubbing ties and protect trunks from deer or rabbit damage where needed.

• Use as a lawn specimen with enough open space to show its branching and autumn colour.
• Plant at a woodland edge with acid-loving shrubs and ferns.
• Place on the upper bank of a pond or in a seasonally wet garden, rather than in permanently deep water.
• Include in a large wildlife garden, away from paving where fallen fruit could be a nuisance.

Garden styles it suits: Woodland, Wildlife garden, Autumn colour, Grand estate, New England and Traditional.

Plant it with: Red maple, Sweetbay magnolia, Summersweet, Winterberry, Highbush blueberry and Cinnamon fern.

Wildlife: Flowers provide nectar and pollen for bees and other insects. The blue-black fruits feed many birds and mammals. Flowers are usually mainly male or female on separate trees, so a fruiting tree generally needs a compatible pollen-producing tree nearby.

• Yellow leaves with green veins often indicate iron chlorosis in alkaline soil. Test the soil; choose a more suitable site rather than relying on repeated iron treatments.
• Leaf scorch or premature leaf fall can follow drought. Water deeply and maintain an organic mulch.
• Transplant failure is a risk because of the root system. Start with a young tree, avoid disturbing the roots and do not move established specimens.
• Leaf spots sometimes develop in humid weather. Collect fallen diseased leaves; established trees rarely need fungicide treatment.

Not known to be toxic to people, cats, dogs or horses. No part is generally recognised as poisonous; the small fruits contain hard stones and are not suitable for pets to eat in quantity.

• Sweet gum (Liquidambar styraciflua)

  Sweet gum has star-shaped, lobed leaves and prickly round seed balls; black gum has unlobed oval leaves and small blue-black fleshy fruits.

• Sourwood (Oxydendrum arboreum)

  Sourwood has finely toothed leaves and long, drooping clusters of white bell-shaped flowers in summer; black gum has mostly smooth leaf edges and inconspicuous spring flowers.

• Water tupelo (Nyssa aquatica)

  Water tupelo usually has larger leaves, often with a few coarse teeth, larger solitary fruits on long stalks and a conspicuously swollen trunk base in wet sites.

Nyssa refers to a water nymph in Greek mythology, while sylvatica means 'of the woods'.

Propagation. Grow from cleaned seed sown outdoors in autumn, or cold-moist stratify seed before spring sowing. Germination can be irregular. Named cultivars are usually propagated by grafting to preserve their characteristics.

Accepted botanical name

Nyssa sylvatica

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Arkansas, Connecticut, Florida, Georgia, Illinois, Kansas, Kentucky, Louisiana, Maine, Maryland and Masachusettes.

Measured

Soil pH 4.5 to 6. Average height 1370 cm.

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