H. VULGARE.—Common Rock Rose. Europe (Britain), North Africa, and West Asia. A widely distributed native plant, of dwarf growth, with linear-oblong, hairy leaves, and usually yellow flowers. H. vulgare nummularium differs in having the leaves green and sub-orbicular, with yellow flowers. H. vulgare barbaturn is of erect habit, with silky, hairy, oval leaves. H. vulgare mutabile bears pale rose flowers, marked with yellow at the base. H. vulgare grandiflorum is remarkable for the large, bright yellow flowers, and is one of the most beautiful and worthy varieties. H. vulgare ovalifolium (syn H. serpyllifolium) bears yellow flowers and ovate leaves, with the margins revolute. H. vulgare hyssopifolium bears reddish flowers, but the colouring varies considerably, and saffron is not uncommon.
The Rockroses are very valuable plants, in that they will succeed on poor, gravelly banks where few other plants could eke out an existence. They cannot withstand stiff soil, nor that at all inclined to be damp, their favourite resorts being exposed, rocky ground, and dry, gravelly banks. Being readily increased from cuttings, which take root well under a hand glass or in a cool house, it is advisable, at least with the more tender forms, to have at hand a stock, so that blanks in the shrubbery may be filled up.
HIBISCUS.
HIBISCUS SYRIACUS (syn Althaea frutex).—Syrian Mallow. Syria, 1596. An old occupant of our gardens, and one that cannot be too freely cultivated. When favourably situated, it often reaches 6 feet in height, with three-lobed, neatly-toothed leaves, and with large, showy blossoms that are borne towards the end of summer. The typical species has purplish flowers, with a crimson spot at the base of each petal, but others, varying in colour from snow-white to purple and blue, are common in cultivation. H. syriacus coelestis bears bright blue flowers, while H. syriacus variegatus has beautifully variegated foliage. Of the double-flowered forms, there are several beautiful and worthy plants, the following list containing some of the best varieties of this popular shrub:—
H. syriacus albo-pleno. " amaranthus. " amplissima. " ardens. " caerulea plena. " carnea plena. " De la Veuve. " elegantissimum. " fastuosa. " Lady Stanley. " Leopoldii. " lilacina plena. " paeoniaeflora. " puniceus plenus. " rosea plena. " spectabilis plena. " violacea.
HIPPOPHAE.
HIPPOPHAE RHAMNOIDES.—Sea Buckthorn, or Sallow Thorn. Though generally considered as a sea-side shrub, the Sea Buckthorn is by no means exclusively so, thriving well, and attaining to large dimensions, in many inland situations. The flowers are not at all conspicuous, but this is amply compensated for by the beautiful silvery-like leaves and wealth of fruit borne by the shrub. In not a few instances, for fully a foot in length, the branches are smothered with crowded clusters of bright orange berries, and which render the shrub during November and December both distinct and effective. It does best in sandy soil, and is readily increased from suckers, which are usually plentifully produced by old plants. For sea-side planting it is one of our most valuable shrubs, succeeding, as it does, well down even to high water mark, and where the foliage is lashed with the salt spray.
HOLBOELLIA.
HOLBOELLIA LATIFOLIA (syn Stauntonia latifolia).—Himalayas, 1840. An evergreen climbing shrub that is more often found under glass than out of doors. In the South of England, however, it is quite hardy against a sunny wall. It grows 12 feet high, with shining green leathery leaves, and fragrant purplish-green flowers. H. latifolia angustifolia has decidedly narrower leaves than the species, but is in no other way different.