=A. citriodora= (lemon-scented).* _fl._ whitish or lilac, very small, in terminal panicles. August. _l._ pale green, lanceolate, agreeably scented, arranged in whorls of threes; branches slender. Chili, 1781. SYNS. _Lippia citriodora_, _Verbena triphylla_.
=ALPINE GARDEN.= A very interesting style of gardening, which succeeds best by imitating Nature as closely as possible. The situation may be an open or a sheltered one. In building a Rock or Alpine Garden, it should be so arranged that all aspects are secured--shady and sunny--fully or in degree only. Pockets and crevices of various sizes may be made, and filled with soil suitable for the subjects to be planted therein, each one having a direct connection with the bulk of the soil; and the constructing material should be arranged with a gentle fall, so that moisture drains towards rather than from the roots. Alpine plants, as a rule, flourish better on a properly constructed rockery than if placed in any other position, because thorough drainage is effected, and the long and fine roots can run down in the crevices, where the soil is cool and moist. Although most alpine plants are naturally exposed to the full action of sun and wind, they should be placed out in early autumn, or early spring, so as to become thoroughly established before the approach of scorching summer weather. Failing materials necessary for the construction of a rockery, many alpines are easily grown in the ordinary border, in a naturally or artificially well drained situation. Excavate to the depth of 18in., put in a layer of stones, broken bricks, &c., 6in. deep; fill up with rich fibrous loam and leaf mould, adding sufficient sand to keep the soil porous. When the desired subjects are firmly planted, cover the surface with small gravel or stone chippings, which, while allowing the rain to penetrate the soil, effectually checks evaporation, and keeps it moist and cool, as well as giving the appearance of rocky _débris_. The effect will be better if the surface is slightly undulated.
=ALPINE ROSE.= _See_ =Rhododendron ferrugineum=.
=ALPINIA= (in honour of Prosper Alpinus, an Italian botanist). ORD. _Zingiberaceæ_. A rather large genus of stove herbaceous perennials, with considerable grace and beauty. Flowers disposed in terminal spikes. Leaves lanceolate, smooth, even, entire, sheathed at the base, and having transverse veins. Roots fleshy, branched, having much of the smell and taste of ginger. The soil can hardly be too rich for the successful culture of these plants. A mixture of equal parts loam, peat, leaf mould, or thoroughly rotted hotbed manure, freely mixed with sharp sand or fine charcoal dust, forms an excellent compost. During the growing season, a top dressing of rotten dung, and a frequent application of weak manure water, prove excellent stimulants. They grow rapidly and consume a great deal of food in the production of so much stem and so many leaves. Unless the former is vigorous and of considerable thickness, it will fail to be crowned with spikes of flower. Alpinias require a high temperature, a rich, light soil, abundance of water, and not a little space, to grow them well. Soon after flowering, the plants will assume the yellow leaf, when water may be gradually withheld; but no attempt should be made to dry them off too severely, even after the stems die down. Nor must they be stored when at rest in a low temperature; in fact, they require as much heat to preserve them in health when resting as at any other time. The best time to divide the plants is after the young shoots have made an inch of growth in spring.