An evergreen tree occasionally 100 ft high in a wild state, with a trunk as much as 11 ft in girth; young shoots angled, clothed with fine white down. Leaves doubly pinnate, 3 to 5 in. long, the main divisions (pinnae) in usually fifteen to twenty pairs, each 1 to 11⁄4 in. long, and bearing thirty to fifty pairs of tiny linear leaflets, which are about 1⁄6 in. long and 1⁄30 in. wide. All the parts of the leaves are covered with the same silvery down as the young shoots, but not so thickly. Flowers fragrant, produced in panicles of globose heads or balls, each panicle 3 to 4 in. long, each head 1⁄6 in. wide, yellow, opening (on outdoor plants) in late winter and early spring. Seed-pods blue-white, 2 to 3 in. long, 1⁄4 to 1⁄2 in. wide, flat.
Native of New South Wales, Victoria, and Tasmania; introduced from Tasmania in 1820. At Kew it has to be given cool greenhouse treatment but is successfully grown in many Irish, Cornish, and Devon gardens, also along the coasts of Sussex and Hampshire. At Abbotsbury, in Dorset, it reached 70 ft in height and produced good seed. Even as far east as Suffolk it has grown and flowered well in the open ground. Really severe winters like those of the early sixties will kill it or cut it to the ground over much of the country but it is, perhaps, our cool and cloudy summers that prevent it from developing its full beauty as a flowering shrub, abundant sun and heat being necessary if the wood is to ripen and produce the embryonic flowers. For this reason the silver wattle is most likely to prove a success in sunny coastal gardens, in a position protected from strong winds, but unfortunately it will not tolerate chalky soils.
It is remarkably beautiful on the French Riviera, especially about Cannes, whence it is that such large quantities of flowering branches are sent to Paris and London as ‘mimosa’. The beautiful silvery, feathery foliage and clear yellow, fragrant flowers make a charming and perfectly beautiful combination.
A. decurrens (Wendl.) Willd. Mimosa decurrens Wendl. – Leaves less hairy, rich green, with the ultimate divisions more widely spaced. A. dealbata is sometimes considered to be a variety of this species, and certainly they are closely allied.