A deciduous tree growing to 30 m (98ft) by 20 m (65ft) at a fast rate. It is hardy to zone 4 and is not frost tender. It is in flower from May to June, and the seeds ripen in October. The flowers are monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and are pollinated by Wind. The plant is self-fertile.
The kernels have a sweet, rich distinctive delicious flavour it makes an excellent dessert nut and is also widely used in confections, cakes etc. Shelling is a problem as they have very hard shells.
Requires a deep well-drained loam and a sunny position sheltered from strong winds. Prefers a slightly alkaline soil. Plants are best suited to deep, rich, slightly acid or neutral soil, with good drainage, but will not succeed on infertile upland soil or on soils with poor drainage. The dormant plant is very cold hardy, but the young growth in spring, however, can be damaged by late frosts. The Black walnut is one of most valuable natural forest trees in the United States. A very ornamental and fast growing plant, it is sometimes cultivated in N. America for its edible seed. Good seed crops are usually produced every other year, though some plants fruit well annually whilst others produce god crops every third year. There are breeding programmes that are seeking to develop cultivars with thinner shells. Trees in the wild commence bearing seeds when about 12 years old. Black walnut have a growing season of about 150 days and an average summer temperature of 16.5°C. There are some named cultivars have been developed for timber and nut production. Plants produce a deep taproot which makes them very drought resistant when established, though they are intolerant of root disturbance.