Forsythia suspensa (Thunb.) Vahl
Synonyms: Syringa suspensa Thunb.
A deciduous shrub of rambling habit, which if trained on a wall will grow 30 ft high, but in the open, and unsupported, forms a mass of interlacing often pendulous branches, 8 or 10 ft high; young branches glabrous, hollow except at the nodes. Leaves mostly simple, 2 to 4 in. long, 1 to 2 in. wide, but occasionally on strong shoots trifoliolate, three-lobed, or two-lobed, coarsely toothed, pointed, the simple leaves rounded or broadly wedge-shaped at the base, the leaflets wedge-shaped at the base; stalk about 1⁄2 in. long. Flowers golden yellow, produced one to as many as six in a cluster from the buds of last year’s wood in late March and early April, lasting a month in beauty; each flower 1 to 11⁄4 in. across. Calyx-lobes oblong-lanceolate, 1⁄4 in. long. Fruits narrow-ovoid, beaked.
Native of China, long cultivated in Japan. It is usual to recognise two varieties:
var. sieboldii Zab. – This is the variety described above. Shoots slender, pendent, rooting where they touch the ground. Leaves rather broad-ovate, usually unlobed. Flowers long-stalked (stalks about twice as long as the buds); petals not so recurved and spreading as in var. fortunei. Possibly a Japanese garden variety. According to Siebold F. suspensa was introduced to Europe by Verkerk Pistorius in 1833, but whether in the pendent-branched form or the erect-branched (also cultivated in Japan) he did not say. To Britain it was introduced shortly before 1857, in which year what is clearly the var. sieboldii was figured in Bot. Mag., t. 4995. According to Rehder, the var. sieboldii was represented in European gardens by short-styled plants (Gartenfl. (1891), pp. 395 – 400). It was probably a plant similar to the var. sieboldii at least in habit, and probably in its long-stalked flowers, that Thunberg took as the type of his Syringa suspensa.
var. fortunei (Lindl.) Rehd. F. fortunei Lindl. – A shrub of stiffer growth, with erect or arching (not so pendulous) shoots. Leaves usually three-lobed or parted on strong shoots, more narrowly ovate than in var. sieboldii. Flower-stalk not much longer than the bud; petals spreading, slightly recurved. Introduced by Fortune from China to Standish’s nursery in 1862. An erect-branched form was also cultivated in Japanese gardens.
The differences between the two varieties given above refer to the plants originally grown in Europe. There are plants now in cultivation that it is difficult to assign to one or the other. F. suspensa var. sieboldii in its characteristic form is, however, still very common in cultivation. It is useful for covering a steep slope, and for using as a climber on house-walls, arbours, etc. It will flower well on a north-facing wall, and assumes a semi-climbing habit if planted near a tree or tall shrub.
f. atrocaulis Rehd. – Young shoots and unfolding leaves of a dark purplish hue; older wood rich brown. Introduced by Wilson from W. Hupeh under W.637, when collecting for the Arnold Arboretum. The plants raised from these seeds seem to have varied somewhat in habit and size of flower (but some so-called inferior forms of atrocaulis may be F. giraldiana, q.v.). The ‘Nymans Variety’ is a very beautiful forsythia with soft yellow, nodding flowers about 13⁄4 in. across, with flat, spreading lobes about 1⁄2 in. wide at the base. It is of erect habit and one of the last forsythias to flower. There are, however, unnamed clones very similar to this.
Two garden varieties of F. suspensa, neither of much value and now scarce, are ‘Decipiens’ and ‘Pallida’, both raised by Späth.