Common name: Slippery Cabbage

Slippery Cabbage, or Aibika, is a fast-growing shrub in the Hibiscus family that produces edible leaves and is native to a wide geographic area extending from Southeast Asia to Melanesia, a region in the Pacific encompassing Papua New Guinea, the Solomon Islands, and New Caledonia.

It grows unattended up to 4 m (13 ft) tall but, in cultivation, is pruned to 1.5-2 m (5-6 ft) to facilitate harvesting the leaves, which are cooked as a vegetable.

There are many varieties, mainly distinguished by leaf shape. The leaves are deep green, large, up to 30 cm (12 in) long and almost as wide, and come either heart-shaped or in various lobed to palmate forms, ranging from shallow to deeply lobed and from smooth to wavy-margined. The leaf stalks and veining colour can also differ by variety, ranging from green to red.

The flowers are like those of Okra and other closely related Hibiscus species, with pale yellow petals and purple centres. When fertilised, they develop into green seedpods that look like Okra.

Edible uses

Cooked vegetable - The leaves and tender leaf stalks are steamed, stir-fried, or used in soups, stews, and curries. If not cooked right away, the harvested leaves and stalks can be stored damp in an airtight container in the refrigerator, where they will keep fresh for up to three days.

Natural thickening agent - Their rich flavour and mucilaginous quality also make them valued for thickening sauces.

Environmental uses

Hedge plant - Commonly grown as a hedge in home gardens, usually spaced closely in rows.

Shade or privacy screen - This forms a dense, edible privacy screen.

Health use

Beta carotene - The cooked leaves and tender stalks contain high levels of beta carotene.

Also a good source of the following:

Folate
Calcium
Magnesium
Potassium

Climate

Grows naturally and is productive in humid tropical climates, but can be grown as an annual in cool climates, generally across areas with annual lows of 12 to 25°C, annual highs of 22 to 35°C, annual rainfall of 1200 to 5000 mm and a dry season of 4 months or less. In warm areas with evenly distributed rainfall, it grows fast and produces lush, green leaves. In arid areas or in the dry season, the leaves quickly become leathery and fibrous.

Growing

New plants are usually started from cuttings taken from selected varieties. Cuttings of mature wood around 50 cm (1.5 ft) long are taken and planted one-third to one-half deep into soil that has been enriched with organic matter. If not planted right away, the cuttings can be left to stand, cut end in water, for a few days, with the water changed daily to prevent stem rot.

Growth performance is best in rich, free-draining clay-loam, loam, sandy-loam and loamy-sand soils of an acid to neutral nature, generally with a pH of 5.0 to 7.0 and on sites with full to partial sun exposure. It has poor tolerance for drought, limestone soils, waterlogging, or shade, which reduce leaf production and increase disease incidence.

Mulching is needed to prevent the soil from drying, but it should be kept a few centimetres clear of the main stem to avoid encouraging stem rot.

It needs manuring and cutting back or replanting every 18 to 24 months to maintain a continuous supply of leaves year-round. Otherwise, it becomes woody and unproductive.

Smooth-margined varieties are more forgiving than lobed or palmate varieties when it comes to harvesting. The latter's leaves need to be harvested very young, as they tend to become tough and fibrous if left on the plant for too long. Harvesting should be carried out in the cooler hours of the day to prevent wilting.

Problem features

It is listed as a weed in at least one reference publication. Still, no record shows it as a serious weed anywhere in the world, despite its widespread cultivation in the tropics. The Hawaii Pacific Weed Risk Assessment (HPWRA) project assesses it as a low weed risk for Hawaii.

Books

• Elevitch, C. R & Wilkinson, K. M. 2000, Agroforestry Guides for Pacific Islands, 1st ed., Permanent Agriculture Resources, Holualoa, Hawaii

• Grubben, G.J.H. & Denton, O.A. (Editors) 2004, Plant Resources of Tropical Africa, Volume 2 : Vegetables, PROTA Foundation, Backhuys Publishers, Leiden

• Hu, S. 2005, Food plants of China, Chinese University Press, Hong Kong

• Parrotta, J. A. 2001, Healing plants of peninsular India, CABI Publishing, Wallingford, Oxfordshire

• Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

• Tindall, H. D 1983, Vegetables in the Tropics, Macmillan Press, London

• Toensmeier, E. 2007, Perennial Vegetables : From Artichokes to Zuiki Taro, A Gardener's Guide to Over 100 Delicious and Easy to Grow Edibles, White River Junction, Chelsea Green Publishing, Vermont

• Walter, Annie & Lebot, Vincent & Sam, Chanel & Ferrar, P. (Paul) & Walter, Annie. Fruits of Oceania et al. 2007, Gardens of Oceania, Australian Centre for International Agricultural Research, [Canberra]