Lonicera japonica Thunb.
Synonyms: Nintooa japonica (Thunb.) Sweet
An evergreen climber of vigorous habit, growing 20 to 30 ft high; stems hollow, twining, densely covered with spreading hairs when young, green or reddish purple. Leaves variable in shape, from elliptic to broad elliptic or ovate, rounded or truncate or cuneate at the base, apex acute or sometimes rounded and then narrowed abruptly to an acuminate tip, 11⁄4 to 31⁄4 in. long, margins ciliate, the blade varying in indumentum from downy or villous above and villous beneath (especially on the veins) to almost glabrous; although normally entire they are not infrequently lobed; leaf-stalk about 3⁄16 in. long. Flowers fragrant, produced from June onwards in pairs from the leaf-axils on peduncles 1⁄2 to 3⁄4 in. long; bracts leaflike, ovate or elliptic, 1⁄2 to 3⁄4 in. long. Corolla 11⁄4 to almost 2 in. long, hairy on the outside, white or purple-tinged, ageing to yellow; limb two-lipped, the upper lip varying from shorter to longer than the tube. Ovary glabrous. Fruits black, not united.
Native of Japan, China, and Korea; for date of introduction see under var. repens. It is a variable species and the above description is a generalised one. The plant (probably a cultivated one) from which Thunberg described the species, had flowers purple outside and leaves hairy beneath, but this typical variety is probably not in cultivation here, all the garden plants having the leaves quite or almost glabrous beneath when mature.
cv. ‘Aureo-reticulata’. – Leaves mostly less than 2 in. long, sometimes pinnately lobed, the veins and midrib picked out in bright yellow. A very effective variegated plant in summer, but often killed back a good deal in winter. It flowers quite freely against a wall. Introduced by Fortune, shortly before 1862.
cv. ‘Halliana’ . – Flowers very fragrant, pure white, ageing to yellow; tube of corolla slightly longer than the upper lip. Leaves slightly hairy on the veins beneath at first, soon glabrous. A vigorous and almost hardy evergreen climber flowering from midsummer until early autumn. It was introduced by Dr George Hall to Parsons’ nursery, Flushing, USA, in 1862, but did not reach Britain until the 1880s. It is the commonest representative of the species in gardens, and the most beautiful.
var. repens (Sieb.) Rehd. L. brachypoda var. repens Sieb.; L. flexuosa Thunb.; L. japonica vat. flexuosa (Thunb.) Nichols.; L. brachypoda DC.; L. chinensis Wats.; L. japonica var. chinensis (Wats.) Baker – Leaves soon glabrous, often heavily tinged with purple beneath (if so, then the stems also reddish-purple). Flowers usually stained purple on the outside, the tube about equal in length to the upper lip or shorter. This variety, which only differs from the type in being less hairy, was introduced from China early in the 19th century in a form with a strong infusion of purple in the stems, leaf-undersides, and flowers, and with a tube of the corolla about equal to or slightly longer than the upper lip. Bot. Mag., t. 3316. This may still be in cultivation, but a commercial plant, while agreeing with this in colouring, has a shorter corolla-tube.
In the eastern USA L. japonica has become ‘a most pernicious and dangerous weed, overwhelming and strangling the native flora and most difficult to eradicate’ (Gray’s Manual of Botany, 8th ed., p. 1334).
L. confusa DC. – This species is allied to L. japonica but is quite distinct in its awl-shaped bracts. Also the inflorescence-axes and ovaries are hairy and the undersurface of the leaves is covered with a close indumentum of short hairs. A native of S. China, naturalised in Jamaica; almost certainly tender. It was originally confused with L.japonica under which name it is figured in Bot. Rep., t. 583, and Bot. Reg., t. 70