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Olearia semidentata Decne.

Modern name

Olearia semidentata Decne.

An evergreen bush of rounded habit 6 to 12 ft high and as much or more in diameter; young shoots slender, clothed with a white, woolly felt. Leaves alternate, linear to lanceolate, pointed, tapered slightly to a stalkless base with a few shallow teeth at the upper half, 112 to 3 in. long, 16 to 58 in. wide, upper surface dark green, wrinkled, lower one clothed with soft, silvery white wool. Flower-heads solitary at the end of the twigs, each one about 2 in. wide, aster­like in form, the numerous spreading or slightly decurved ray-florets pale purple and about 34 in. long by 16 in. wide; disk-florets of a darker, more violet-purple, forming a conspicuous circular centre to the flower-head 12 to 34 in. wide. The outer scales of the involucre are linear, pointed, closely set in about three rows, and almost hidden by a white cottony down. Bot. Mag., t. 8550.

Native of the Chatham Islands; introduced to England in 1910 by Major A. A. Dorrien-Smith, who gives a very interesting account of a visit made to the native habitat of this beautiful shrub in the Kew Bulletin, 1910, p. 120. On this occasion he found a white form, var. albiflora Dorrien-Smith. Since its introduction, O. semidentata has spread in cultivation and become, in the milder parts of the British Isles, one of the most popular of the genus, which it well deserves to be. It first flowered at Tresco Abbey in Scilly in July 1913.

In colour beauty of blossom this surpasses all other olearias I have seen in cultivation. It is not adapted for the open air in places with a climate similar to that of Kew, only surviving there the mildest winters and even then not unscathed. It likes a light, well-drained or even stony soil. Closely related to O. chathamica (q.v.).

The clone grown in the British Isles from Major Dorrien-Smith’s introduction, illustrated in the Botanical Magazine, and described above, differs from typical O. semidentata in several ways, especially in its larger, less clustered flower-heads and much more woolly involucral bracts. In these differences it approaches O. chathamica and it is possible that the plants known in cultivation as 0. semidentata are of hybrid origin (O. semidentata × O. chathamica) and not the pure species. The introducer is likely to have picked out an especially striking and floriferous variant for introduction and a plant of hybrid origin would be likely to exhibit vigour and thus also these desirable garden qualities.



Other species in the genus