Hibiscus or Rosemallow is a large genus of about 200-220 species of flowering plants in the family Malvaceae, native to warm temperate, subtropical and tropical regions throughout the world. The genus includes both annual and perennial herbaceous plants, and woody shrubs and small trees. The leaves are alternate, simple, ovate to lanceolate, often with a toothed or lobed margin. The flowers are large, conspicuous, trumpet-shaped, with five petals, ranging from white to pink, red, purple or yellow, and from 4-15cm broad. The fruit is a dry five-lobed capsule, containing several seeds in each lobe, which are released when the capsule splits open at maturity.
Any ordinary garden soil will do as long as it isn't excessively dry. Tropical Hibiscus that are grown in greenhouses need a sunny location and a minimum winter temperature of 45-50F. In the spring they should be pruned by shortening the side shoots by two-thirds and when they have started into new growth, a 55-65F temperature should be maintained. Large plants may be grown in large pots or tubs, or they may be planted in a bed in the greenhouse and either grown as bushes or trained to wires or a trellis on a wall. Tropical Hibiscus: Cuttings, 3in long, can be inserted into sand and peat moss in March and April in a propagating case in the hothouse. They are kept there until they form roots, they are then potted in 3in pots and, later, in larger pots. When they are 6in long, the main shoots and side branches are pinched to encourage bushy growth. Hardy perennials: Seeds can be sown in drills 1in deep in light soil in May or June. The seedlings are transplanted, 6in apart, in a nursery bed and set in their final positions in the fall. They may also be divided.