Juglans nigra
Black walnut
- Height × spread
- 24m × 15m
- Position
- Full sun
- Hardiness
- Very cold to -20C (RHS H6)
- Flowers
- Autumn
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This handsome walnut tree has large, pinnate leaves and deeply furrowed bark. This is brown on a young tree and black on an old one, hence the common name. The leaves are held in handsome sprays and are a good rich, shiny, green, turning yellow in the autumn, though the colour may not be long-lasting. The tree can reach a height of 16m (50ft) in 20 years. This walnut produces a resin in its leaves considered to be a good fly repellent; consequently, in old houses you might find a walnut planted close to the kitchen to deter flies. If the leaves are crushed and sniffed they give off an aroma that is said to clear the head. Italians have been known to recommend that you place a few leaves beneath your sun hat as a shield against the effects of the sun.
- Foliage colour
- Green
- Autumn foliage
- Yellow
- Fruit colour
- Green
- Variegated
- No
- Scent
- Yes
- Shape
- Bell
- Height
- 24m
- Spread
- 15m
- Height in 10 years
- 8m
- Spread in 10 years
- 5m
- Season of interest
- Autumn
- Flowers in
- Autumn
- Evergreen
- Deciduous
- Garden style
- Scented garden
- Sun or shade
- Likes full sun, tolerates part shade
- Soil type
- Clay, Loam (normal)
- Soil pH
- All types
- Drainage
- Moisture retentive soil, Well drained soil
- Hardiness
- Very cold to -20C (RHS H6)
- Borders & containers
- Borders
- Use for
- Architectural, Bird attraction
- Deer
- May be nibbled by deer
- Hazards
- No
Spring
Spring - late · Outdoors
Feed young plants with slow release fertiliser
Spread a slow release fertiliser around the base of the plant to the edge of the foliage spread, so that it can feed the roots. It is helpful for this to be applied for several years.
This is a simple way to provide a nutrient boost until the plant becomes well established.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Summer
Summer - late · Planting
Prune to maintain the tree
Keep the plant looking attractive and healthy by removing dead branches, branches that cross or rub each other, and those which spoil its appearance.
Prune in late summer as the tree is less likely to be damaged, or to begin to bleed from the wood that has been cut.
Planting & general
Outdoor planting · Planting
Add root growth stimulant to the planting hole
Mycorrhizal fungi helps roots establish quickly, so they absorb water and nutrients more efficiently. It comes as a powder, granule or gel. Add to the planting hole or container, and to the plant's rootball before planting in the hole. For "bareroot" plants use a gel.
Planting
Protect & support young trees
Attach a newly planted tree or tall shrub over 1m to a tree stake to give support and prevent windrock. Use a tree guard to stop tree bark being eaten by animals, especially in areas with deer - removing bark injures a tree and in worst case can kill it.