Iberis sempervirens L.
An evergreen sub-shrub 6 to 12 in. high, of spreading habit, free from down; stems slender, thickly furnished with linear or oblanceolate leaves which are 1⁄2 to 2 in. long, 1⁄8 to 3⁄16 in. wide, blunt or rounded at the apex, not toothed. Flowers white, produced from April to June in racemes at first flattish and 1 to 11⁄2 in. wide, but elongating later; main flower-stalk 2 to 4 in. long with the flowers at the terminal half. Seed-pod roundish or obcordate, 1⁄4 in. wide, notched at the top.
Native of S. Europe and W. Asia; introduced in 1731 and for very many years a favourite in gardens and the commonest of these sub-shrubby candytufts. It is very hardy and covers itself every spring with a sheet of white flowers. It is well distinguished from the two preceding species by its narrow leaves.
var. garrexiana (All.) Cesati I. garrexiana All. – Of dwarfer more compact habit than typical I. sempervirens, with somewhat narrower leaves, sometimes pointed at the apex. Described from the Maritime Alps, where it grows near Garessio and on the Col di Tenda; also found in the Pyrenees.
cv. ‘Little Gem’ (‘Weisser Zwerg’). – A dwarf, dense shrublet with short narrow pointed leaves. Flowers pure white, rather small, in narrow trusses. Raised in Germany.
cv. ‘Snowflake’. – A compact shrub up to 1 ft high and 2 ft across. Leaves dark green, oblong. Flowers in trusses about 2 in. wide which elongate before all the flowers are expanded.
I. saxatilis L. I. vermiculata Willd. – A dwarf plant 3 to 5 in. high with hairy shoots. Leaves linear, 3⁄8 to 1 in. long, fleshy, almost cylindrical in cross-section, blunt or sharply pointed at the apex and usually ending in a short mucro, ciliate or quite glabrous. The inflorescences elongate in the fruiting stage as in I. sempervirens but the two species are easily distinguished by their foliage. Native of the mountains of S. Europe from Spain to the Crimea. Admirable for the rock garden.
I. corifolia (Sims) Sweet I. saxatilis var. corifolia Sims – The identity of the plant figured in the Botanical Magazine (1826), t. 1642, as I. saxatilis var. corifolia, is uncertain, the plate being a poor one and the description scanty. The iberis that Farrer knew as I. corifolia was a form of I. saxatilis but was not the plant of the Botanical Magazine. Many of the plants once grown as “I. corifolia” were really the hybrid I. ‘Correifolia’ (see below).
I. ‘Correifolia’. – A vigorous hybrid raised by H. Turner in the Botanic Garden, Bury St Edmunds, before 1857. Leaves spathulate, dark glossy green, up to 11⁄2 in. long. Flowers borne towards the end of May in corymbs which gradually elongate into rounded heads about 3 in. long. It grows 8 in. to 1 ft high and up to two yards across. One parent was almost certainly I. sempervirens; the other perhaps I. tenoreana. It seems to be now rare m gardens but was much grown in the 19th century, often as “I. corifolia”.