Cistus × lusitanicus Maund
A hybrid between C. ladanifer and C. hirsutus which has arisen in gardens and is also found wild in Portugal. There are two forms in cultivation of which the best known is:
cv. ‘Decumbens’. – A spreading bush usually seen below 3 ft in height but taller in semi-shade; young stems gummy, sparsely hairy at first. Leaves stalkless, clammy, narrowly oblong-lanceolate to oblong-oblanceolate, bluntly pointed to rounded at the apex, 1 to 21⁄2 in. long, 1⁄4 to 3⁄4 in. wide; three-nerved and clasping the stem at the base; upper surface dark green with a dull sheen, lower surface paler, with a few scattered hairs. Flowers white with a crimson blotch at the base of each petal, about 21⁄2 in. across, borne in terminal clusters each of three to five flowers; sepals five, downy on the outside, clad within with silky hairs, especially near the edges.
The origin of this cistus is unknown but there can be little doubt that it is the plant figured and described in Maund’s The Botanic Garden, Vol. 9, No. 733, fig. 3 (c. 1845) as C. lusitanicus var. decumbens. It is recorded that at Kew, it survived the great frosts of 1886. It was later confused with C. × loretii (q.v. under C. ladanifer) and this is the name under which it appeared in the first edition of this work and under which it was figured in the Botanical Magazine, t. 8490 (1913). It is only in the past thirty years or so that it has come to be known again by its correct name. C. × lusitanicus ‘Decumbens’ is one of the élite of cistuses, valuable for its low, spreading habit and for bearing its flowers freely over a long period. It is not reliably hardy, but should survive the average winter.
A second form of C. ladanifer × hirsutus is also in cultivation. It was once grown under the erroneous name of “C. recognitus”, which is a synonym of C. × glaucus, a hybrid between C. laurifolius and C. monspeliensis. This cistus – now grown as typical C. lusitanicus – is easily distinguished from ‘Decumbens’ by the smaller and fainter blotch at the base of each petal. It also differs in its leaves, which are oblong-lanceolate, taper-pointed and lack the dull sheen which characterises the other cistus. Its habit, too, is more erect.
It should be pointed out that under the rules of botanical nomenclature the name C. × lusitanicus Maund is invalid, the same epithet having been used earlier by Philip Miller for some unidentified cistus. It is best retained, however, until a valid name is published.