This species is represented in cultivation by the following variety:
var. parvifolia Sealy P. sieberi Hort., not Benth. – An aromatic shrub or small tree up to 12 ft or so, minutely glandular in all its parts. Leaves of papery texture, ovate, broad-ovate, or broad-elliptic, mostly 3⁄8 to 5⁄8 in. long, 5⁄16 to 1⁄2 in. wide, but occasionally up to 1 in. long, dark green above, undersurface bright green, conspicuously gland-dotted, downy on the midrib and main veins, margins with one or two teeth on each side, or entire, finely ciliate; petiole 1⁄8 to 1⁄4 in. long. Inflorescence a short, terminal cluster of about eight flowers, or sometimes paniculate owing to the production of additional racemes from the uppermost leaf-axils; bracts soon deciduous. Calyx densely white-glandular on the outside. Corolla lilac-mauve, 1⁄2 in. or slightly more wide, almost as long, glandular on the outside and with finely ciliate margins; tube bell-shaped from a narrow base; upper lip rounded, its two lobes overlapping; median lobe of lower lip obovate-oblong, truncate, slightly longer than the ovate, obtuse lateral lobes. Bot. Mag., t. 9687.
P. melissifolia is a native of S.E. Australia. The plant described here, though agreeing best with that species, differs from the typical state in its much smaller leaves, fewer-flowered racemes, and in having the corollas almost glabrous outside. It was obtained by Kew in 1929 from Messrs Duncan and Davies of New Zealand under the name “P. sieberi”, but is quite distinct from the species so named by Bentham. It is not matched by any wild specimen in the Kew or British Museum herbaria, and its provenance is unknown. It was named P. melissifolia var. parvifolia Sealy in the article accompanying the plate in the Botanical Magazine.
P. melissifolia var. parvifolia is one of the finest of the mint bushes. Although certainly not hardy it is probably no more tender than P. rotundifolia, from which it differs in the larger, thinner, differently shaped leaves and the paler corolla, which is almost glabrous except for the ciliate margins. It grows quickly and is easily propagated by cuttings. It received an Award of Merit in 1940 as a shrub for the cool greenhouse when shown from Kew as “P. sieberi”. It is possibly still grown under that name in some gardens.