Balf.f & W. W. Sm.
Buddleja farreri is a xerophytic deciduous shrub endemic to Kansu, China, discovered by Reginald Farrer in 1915. Farrer described the shrub's habitat as "..the very hottest and driest crevices, cliffs, walls and banks down the most arid and torrid aspects of the Ha Shin Fang".  Farrer sent seed to the UK shortly afterwards, and it is from this consignment that all the British specimens have been derived.
B. farreri was one of five species sunk as Buddleja crispa by Leeuwenberg in 1979,  and later treated as such in the Flora of China;  however the original epithet is widely retained in horticulture.
B. farreri is a deciduous shrub of sparse habit which, left unpruned, grows to a large size. The flowers appear on the old wood before the leaves at the nodes of the previous year's growth, during April in the UK. The lax panicles are < 20 cm in length and pale lavender in colour. The leaves are initially white, owing to a dense coating of hairs, but ultimately become almost glabrous, with a dark green upper surface; the underside remains white and tomentose. Their size and shape are variable, depending on the type of shoot bearing them. Strong shoots from the base will bear large stipules, and broad, winged petioles, very different from those on ordinary shoots.
Farrer summarized the plant as a "noble bush with ample flannely foliage", however Bean noted that it is probably the cooler, damper UK climate which prevents the shrub from making the striking display that so impressed Farrer in China. 
The shrub is hardy in southern Britain, although shoots are killed in severe winters. The plant is self-fertile, and can produce copious viable seed. Softwood cuttings can be struck in June. Hardiness: USDA zones 8–10.
- Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London
- Farrer, R. (1917). On the Eaves of the World. London, Edward Arnold.
- Cotton, A. D. (1947). The spring-flowering buddleias (sic). R H S Journal, Vol 72 1947 pp 428-430.
- Leeuwenberg, A. J. M. (1979) The Loganiaceae of Africa XVIII Buddleja L. II, Revision of the African & Asiatic species. H. Veenman & Zonen, Wageningen, Nederland.
- Li, P. & Leeuwenberg, A. J. M. (1996). Loganiaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 15. Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA. ISBN 978-0915279371 online at www.efloras.org
- Stuart, D. D. (2006). Buddlejas. RHS Plant Guide. Timber Press, Oregon. ISBN 978-0-88192-688-0