A tree 80 to over 100 ft high, with a wide-spreading head and a tall dark trunk, with deeply furrowed bark; young shoots downy. Leaves 1 to 2 ft long, composed of eleven to twenty-three leaflets, the terminal odd one often absent; leaflets fragrant when rubbed, 2 to 5 in. long, 3⁄4 to 2 in. wide, ovate or oblong lance-shaped, obliquely rounded at the base, long and taper-pointed, unevenly toothed, glossy and glabrous above except when quite young, downy beneath; common stalk minutely downy. Male catkins 2 to 4 in. long. Fruits globose or slightly tapered at the base, solitary on the stalk or in pairs, 11⁄2 to 2 in. thick, not downy. Nuts 1 to 11⁄2 in. across, broader than long.
Native of the eastern and central United States; introduced early in the 17th century. Next to the common walnut this is the best known in the genus. Its nuts are of no value as food, but it is a more ornamental tree than J. regia, thriving almost as well in the south-eastern parts of this country as in any of its native haunts. As a young tree the black walnut is particularly handsome, with its shapely pyramidal habit and large pinnate leaves. One of the most valuable of the world’s timber trees, it is now becoming rare in the wild.
The magnificent tree in Marble Hill Park, Twickenham, mentioned in previous editions, measures 88 × 163⁄4 ft (1968); when Elwes measured it in 1905 its dimensions were 98 × 141⁄4 ft. At Mote Park, Maidstone, Kent, he measured a tree of 101 × 121⁄2 ft in the same year; there is still a fine spreading specimen there but its measurements are 74 × 12 ft (1965). The following are some of the other notable specimens recorded recently (the measurements dating from the 1950s were made by the late Maynard Greville): Kew, 72 × 101⁄4 ft (1967); Syon House, London, 70 × 163⁄4 ft (taller until recently shortened) (1967), and two others of lesser girth; Albury House, Surrey, 82 × 141⁄2 ft (1968); Much Hadham Rectory, Herts, pl. c. 1820, 80 × 193⁄4 ft., with a bole of 9 ft (1964); Stansted Hall, Essex, 60 × 16 ft (1951); Hatfield Forest, Takely, Essex, 105 × 14 ft (1952); Hartwell House, Aylesbury, Bucks, 99 × 131⁄2 ft (1957); University Botanic Garden, Cambridge, 75 × 93⁄4 ft (1969); Pusey House, Oxon, 90 × 151⁄2 ft a superb tree (1968); Oxford Botanic Garden, 88 × 93⁄4 ft, (1970); Hartwell House, Aylesbury, Bucks, 99 × 131⁄2 ft (1957); Corsham Court, Wilts, 77 × 131⁄4 ft (1965); Middle Woodford Rectory, Wilts, pl. c. 1820, 70 × 141⁄2 ft (1967). A tree at Brahan Castle, Ross and Cromarty, measures 60 × 93⁄4 ft (1970), a remarkable size for such a northern locality.
cv. ‘Alburyensis’. – An interesting variation from the type grows at Albury Park, near Guildford; this bears its fruits in clusters like J. cinerea, sometimes as many as six together, and it is also distinct in its pendulous branches. This tree measures 70 × 111⁄2 ft (1966).