Photo: John Rusk from Berkeley, CA, United States of America — CC BY 2.0 · source
Survives zone 6 through 9
Walnut — excellent; butternut rich and oily. Rootstock.
- Hardiness
- Zone 6 to 9
- Habit
- Tree
- Edible part
- Nut
- Ripens
- Sept–Oct
- Mature size
- Large tree — NOT containerable
- Light
- Full sun
- Soil pH
- 6.0–7.5 (near-neutral; lime-tolerant)
- Environment
- Temperate
- Status
- Both wild and cultivated
- Years to fruit
- 5–10 yrs
- Pollination
- Monoecious but HETERODICHOGAMOUS — a 2nd cultivar of the opposite type greatly improves set
Growing guide
Fertilizing. Bare-root trees need only a light top-dressing of compost at planting; from the second year an annual spring compost application meets nitrogen needs, and mature trees (3+ years) benefit from an early-spring feed of 5-7 lbs urea or 90-150 lbs manure spread beneath the canopy.
How it spreads. Deep-taprooted with no suckering habit; not ranked as a weed risk, though nuts are widely cached and floated by squirrels, jays, and water along creeks, letting it naturalize slowly in riparian corridors.
Growing tips. Roots and leaf litter release juglone, an allelopathic compound toxic to many nearby plants (notably apples and white pines), so avoid underplanting. The taproot resents disturbance, so plant young stock in its permanent spot; keep the trunk base dry to prevent crown rot, and watch for crown gall and walnut blight, which is worse in wet, humid spring weather.