Gymnocladus dioica (L.) K. Koch

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Gymnocladus dioica' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/gymnocladus/gymnocladus-dioica/). Accessed 2024-03-28.

Common Names

  • Kentucky Coffee-tree

Synonyms

  • Guilandina dioica L.
  • Gymnocladus canadensis Lam.

Infraspecifics

Other taxa in genus

Glossary

calyx
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
androdioecious
With only male or only hermaphrodite flowers on individual plants.
inflorescence
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
linear
Strap-shaped.
midrib
midveinCentral and principal vein in a leaf.
ovate
Egg-shaped; broadest towards the stem.
simple
(of a leaf) Unlobed or undivided.

References

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Recommended citation
'Gymnocladus dioica' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/gymnocladus/gymnocladus-dioica/). Accessed 2024-03-28.

A deciduous tree up to 110 ft high, with a trunk 6 to 10 ft in girth, usually branching low down, and forming a narrow, rounded head. Branchlets downy when young, light grey, marked by numerous small scars. Leaves up to 3 ft long and 2 ft wide, bipinnate, the two lowest pairs of pinnae being simple leaflets, but the upper ones composed of four to seven pairs of leaflets; the leaflets are ovate, 112 to 212 in. long (the two lowest pairs considerably larger), grey-green and hairy beneath, principally on the veins and midrib. The tree is dioecious, the panicles of the female tree being 8 to 12 in. long, 3 to 4 in. wide, narrowly pyramidal; flowers downy, 34 to 1 in. long; petals greenish white, calyx not quite so long as the petals, tubular at the base, with five linear teeth. In the male tree the inflorescence is about one-third the length of the females. Pods 6 to 10 in. long, 112 to 2 in. wide.

Native of the eastern and central United States; cultivated in England before the middle of the 18th century. In its foliage it is perhaps the most beautiful of all hardy trees. It is perfectly hardy in the south of England, but grows extremely slowly, and rarely flowers. It evidently needs more summer heat than it gets here, for there are fine specimens both in France and Germany suggesting in their leafless state the habit and branching of the horse chestnut. In autumn a curious effect is produced by the leaflets falling off and leaving the naked common stalk on the branches for some time. In winter, young trees have a very distinct and rather gaunt appearance, the branches being few, thick, and rough. It likes a deep rich soil and is propagated by imported seeds. The common name is said to have originated through the people of Kentucky and Tennessee at one time roasting and grinding the seeds to make a beverage like coffee.

The largest specimens in Britain so far recorded are all in the south-eastern part of the country. They are: Nymans, Sussex, 55 × 5 ft (1966); Kew 47 × 434 ft and 37 × 3 ft (1964–6); Dulwich College Road, London, 45 × 2 ft (1957); Linton Park, Kent, 47 × 234 ft (1965). There is an old tree in the Oxford Botanic Garden which is dying back; it measures 49 × 434 ft (1970). The best specimen in the country was at Claremont, Surrey; it attained 60 × 7 ft and flowered regularly, but no longer exists. In Eire there is one at Ashbourne House, Co. Cork, measuring 46 × 412 ft (1966).

From the Supplement (Vol. V)

specimens: Kew, 56 × 514 ft (1973) and another 50 × 534 ft (1978); Archbishop’s Palace, Lambeth, London, 52 × 334 ft (1985); Battersea Park, London, ten trees, the best 48 × 5 ft (1983); Brompton Cemetery, London, 40 × 418 ft (1983); Dulwich College Road, London, 40 × 3 ft (1976); Linton Park, Kent, 72 × 412 ft (1984); Nymans, Sussex, 59 × 5 ft (1977); Oxford Botanic Garden, 44 × 434 ft (1981).


'Variegata'

Bean (1976) dismissed this white-variegated form, as being ‘of no beauty’. But opinions change, and today the tree is regarded with admiration by many for its ghostly white presence in summer. David West (Instagram post, July 2023) says that ‘the foliage does not bear close scrutiny, but the mature tree at distance is every bit as exhilarating as a Callery Pear in February.’ On emergence the foliage is a ‘delicious soft pink’ (Houtman 2004). Sadly rare, due to difficulty in propagating the clone, only four specimens are listed in the Tree Register of Britain and Ireland, with the champion being a tree of 15.6 m × 110 cm girth specimen in the Sir Harold Hillier Gardens (Tree Register 2023). The origin of this striking tree seems to be unknown, and it is possible that it is not in cultivation in North America.