Hibiscus

This is a group of hardy and tender shrubs and annual and perennial plants that come from Asia and tropical East Africa. These plants flourish in sunny positions. Tropical Hibiscus can only grow in climates that are frostless, such as Hawaii, southern California and southern Florida. They can form shrubs up to 30 feet tall. They have evergreen leaves, sometimes marked with cream or rose and bear large, trumpet-shaped flowers that are pink, yellow, scarlet, or crimson in the spring and summer. They will flourish in any fairly good soil. Tropical Hibiscus can also be grown in greenhouses. H. Rosasinensis (Rose of China) is very common in Hawaii and is planted freely in Florida and southern California. They thrive only in frostless regions or nearly so. H. cannabinus, which has yellow and red flowers, is a source of fiber and yields edible seeds. H. Eetveldeanus has red stems and leaves and produces magenta-red flowers. H. mutabilis (Cotton Rose, Confederate Rose) has white or pink flowers that turn red in the evening. H. tiliaceus has yellow flowers that change later in the day to a pinkish hue. Hardy perennials can grow about 6 feet tall. They have oval or spear-shaped fuzzy leaves and bear large, trumpet-shaped, pink or white flowers in the summer. They can be planted in regular garden soil in the autumn or spring. The best perennial Hibiscus is H. Moscheutos (the Rose Mallow or Swamp Hibiscus). It grows natively throughout eastern North America in brackish marshes. This and its related kinds are useful for planting near the sea and for planting in raised parts of bogs as well as for setting in ordinary soils that are not dry. Some of the best hybrids may produce flowers that measure 10 to 12 inches across; they are described below in the varieties section. Hardy flowering shrubs can grow 10-15 feet tall and they are deciduous (leaf-losing). Their dark green leaves are oval and deeply notched. They produce bell-shaped, single or double flowers that come in reds, blues or whites in late summer. They may be planted in early fall or spring in well-drained soil. Very little pruning is necessary, but the shoots of overcrowded bushes should be thinned out in the spring. H. syriacus (the Rose of Sharon or Shrub Althaea) is one of the best flowering shrubs of late summer. When well developed, it blooms very freely and provides a beautiful show at a time when few shrubs are in bloom. Annual Hibiscus can be grown in well-drained garden soil. H. Tritonum's (Flower of an Hour) flowers are short-lived, pale yellow or white with dark centers. H. Sabdariffa (the Roselle or Jamaica Sorrel) is grown in the warmest areas of the South for its immature calyces, which are used in making acid jellies, in drinks and as a substitute for cranberries. H. esculenta is an annual variety that's grown for its edible seedpods known as Okra or Gumbo and are used in soups and stews and for other culinary purposes. Okra is basically a crop for warm climates, though it can be grown successfully wherever it is suitable to grow Cucumbers and Melons outdoors. It grows 3 to 7 feet and can live in a variety of soils.

Pot Cultivation

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 45-50 degrees. 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- to 65-degree 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. H. moschuetoes, the Rose Mallow or Swamp Hibiscus, can be grown in 5- to 20-gallon containers of wet soil or under up to 6 inches of water in a water garden. It should be located in sun or partial shade.

Propagation

Tropical Hibiscus: Cuttings, 3 inches 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 3-inch pots and, later, in larger pots. When they are 6 inches long, the main shoots and side branches are pinched to encourage bushy growth.
Hardy perennials: Seeds can be sown in drills 1 inch deep in light soil in May or June. The seedlings are transplanted, 6 inches apart, in a nursery bed and set in their final positions in the fall. They may also be divided.
Annual varieties: Seeds may be sown in rows that are 4-6 feet apart in fertile soil.
Okra: Sowing should be done when the weather is completely warm and settled. Seeds of H. esculentus should be planted a few inches apart and about an inch deep in rows spaced 4 to 5 feet apart. The plants should be thinned to stand 2 to 3 feet apart. These distances are meant for tall varieties; dwarf varieties, which bear less profusely, may be spaced closer. Frequent cultivation throughout the summer should be practiced. The pods are harvested while still young and tender. A long succession of picking is provided through the summer and until the coming of frost.
Hardy flowering varieties: Cuttings can be inserted into a sand bed in the summer and set in a cold frame or greenhouse which is kept closed until roots have formed. They are then planted in a nursery bed and finally they are moved to their permanent spot. Named varieties may also be grafted on the common kind in March. These plants can also be propagated by hardwood cuttings taken in the fall.