This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Handsome herbs with simple entire opposite and alternate leaves and cymose usually bracteate flowers. Calyx deeply 5-lobed, often prismatic or angled. Corolla salver-shaped with a long slender tube and wedge-shaped lobes twisted in bud. Cells of the capsule 1-seeded. An exclusively North American genus, contributing some of the showiest denizens of our gardens. The name is from flame, in allusion to the brightcoloured flowers.
1. Ph. paniculata. - A tall perennial with numerous slender erect glabrous simple stems, ovate or oblong-lanceolate acuminate leaves, and large terminal panicles of flowers. Calyx-lobes slender, finely pointed. Ph. acuminata (fig. 170) is a variety with the stems and under-side of the leaves hairy, the latter are also broader and more pointed. This handsome species varies in the colours of its flowers from lilac, pink, or purple, to white, and, crossed with the next, has given birth to the numerous fine varieties now in cultivation. Many of these are strikingly beautiful from the effective contrasts of colour they exhibit. Some of the white-flowered varieties especially, with a crimson, violet, or purple eye, are unsurpassed for brilliancy amongst herbaceous plants. The self or uni-coloured varieties range from the purest white, through cream, salmon, lilac, pink, and purple, to crimson, and to these may be added many splendid bicoloured or variegated varieties.
2. Ph. maculata. - This is very near the last, differing in its narrower oblong panicle and scarcely-pointed calyx-lobes. The stems are dwarfer and spotted with purple, and the flowers sweet-scented. The normal tint of the flowers is purple, but they vary in colour, and a white variety has been described as a distinct species under the name of Ph. suaveolens. Then there is the form with a more pyramidal inflorescence called Ph. pyramidalis. The garden varieties of this and the preceding are so blended and intermixed that it is now impossible to refer them to their respective species. Moreover, the typical plants are almost unknown out of botanical collections. Ph. decussata is a name applied to some of the hybrid varieties. Ph. divaricata, syn. Ph. Canadensis, is a plant of more straggling habit, with clammy oblong-ovate leaves and a loose inflorescence of pale lilac or bluish flowers with notched petals; and Ph. Carolina and Ph. ovata have semi-erect smooth stems and foliage, and small terminal crowded cymes of pink or purplish flowers with entire rounded petals.
Fig. 170. Phlox acuminata. (1/6 nat. size.)
3. Ph. subulata (fig. 171). - This beautiful dwarf species grows in dense tufts, producing its pink, purple, or white flowers, with a darker centre, in great profusion in early Spring. Leaves very narrow and usually clothed with hairs. But the variety called setacea has them nearly or quite smooth. There are white varieties in cultivation, under the names Nelsonii and nivalis. Ph. frondosa of gardens is a variety of this species. North America.
Fig. 171. Phlox subulata. (1/3 nat. size.;
Fig. 172. Phlox Drummondii. (1/4 nat. size.) x 2
4. Ph. reptans, including Ph. verna and Ph. stolonifera.-A creeping not tufted species, with obovate or rotundate rather thick nearly smooth leaves. Flowering stems from 6 to 12 inches high, clammy-pubescent. Flowers reddish purple, in small cymes; lobes of the corolla entire. North America.
5. Ph. Drummondii (fig. 172). - This is the only annual species in cultivation, and a charming dwarf plant, now, perhaps, more universally grown than any other of its class. It is equally rich in varieties with the perennial species, and one of the most profuse-blooming plants we can call to mind. There is about the same range of colour in the varieties, and it includes some very handsome streaked and marbled ones. It is a native of Texas, and not quite so hardy as the other species.