The genus Buddleia was named in honour of the Rev. Adam Buddle, onetime vicar of Farnbridge, in Essex. The species are small trees and shrubs (rarely herbs) with often angled or winged stems and opposite, usually downy or woolly leaves; they are found in S. America, S. Africa, and E. Asia. In the cultivated species the flowers are produced in terminal and axillary racemes or panicles, on which they are grouped densely in close clusters, except in B. globosa, where they appear in globular heads. The calyx is bell-shaped, four- or five-toothed, or lobed; the corolla tubular, with four lobes, often withering on the stalk and persisting. Stamens four. Seed-vessel a capsule of two valves splitting from the top.
The buddleias, provided the climate is suitable for them, are easily cultivated. They all like a rich, loamy soil and a sunny position, and are easily propagated by cuttings of late summer growths, or by seeds. Those species which flower on the growths of the year may be pruned back in spring before growth commences. For B. davidii and its garden varieties this pruning is necessary in order to get strong shoots and panicles. The buddleias that flower on the previous season's wood may be lightly pruned after flowering.
Buddleias not described in the following notes are: B. asiatica Lour., a slender graceful shrub with long panicles of white, exquisitely fragrant flowers produced in winter and early spring. It is best regarded as a shrub for the cool greenhouse, though in the mildest parts it might be tried on a south or south-west wall. B. madagascariensis Lam., native of Madagascar, with terminal panicles of orange-yellow flowers and violet-coloured berries, is very tender but is grown on a wall at Trengwainton, near Penzance.
'Margaret Pike' is a hybrid between the above species, raised by A. V. Pike and given an Award of Merit in 1953 as a winter-flowering shrub for the cold greenhouse.
From the Supplement (Vol. V)
Buddleia and a few related genera are regarded by some authorities as constituting a separate family – the Buddleiaceae (Buddlejaceae), close to the Loganiaceae but differing in wood anatomy and indumentum.
Linnaeus originally spelt the generic name as 'Buddleja', but until quite recently the spelling was almost universally amended to 'Buddleia' (or by some botanists to 'Buddlea' – the spelling that Linnaeus should in fact have used). The letter 'j' in Buddleja is simply a typographic variant of 'i', also seen in old texts in the Latin genitive singular of nouns in -ius, e.g., 'filij' or in lower case Roman numerals, e.g., xiij for 13.
The Chinese species of Buddleia are revised by A. J. M. Leeuwenberg in: 'Loganiaceae of Africa XVIII. Buddleia II. Revision of the African and Asiatic Species', Meded. Landbouwhogesch. Wageningen 79(6), 1979.
In the introductory note mention was made of the hybrid B. asiatica × B. madagascariensis. This has botanical status as B. × lewisii Everett.