Mesembryanthemum crystallinum Seeds | Ice Plant
LATIN NAME: Mesembryanthemum crystallinum
COMMON NAME: Ice Plant
Plant Profile
The ice plant is a low, spreading annual of the fig-marigold family, native to the winter-rainfall deserts of South Africa and now naturalised around the Mediterranean and in California. It grows ten to thirty centimetres high and spreads to a metre, with fleshy, glistening leaves covered in large, clear blister cells that catch the light like frost.
The flowers are small, white or pale pink and daisy-like, opening in the middle of the day and closing at night, and they appear from spring into summer. The whole plant is succulent and salty to the taste, and it dies back after setting seed, leaving a mat of dry stems. It is one of the few plants whose name describes exactly what it looks like.
Science & Biotechnology
The ice plant is a classic subject in the study of crassulacean acid metabolism. It is normally a C3 plant, but when it is stressed by salt or drought it switches to CAM, opening its stomata at night and fixing carbon dioxide into malate, which it releases during the day with the stomata shut. That switch can be induced within a week in a laboratory, which makes the species a convenient model for studying the regulation of CAM.
The bladder cells on the leaves and stems store water and salt, and they give the plant its glitter. Sodium is accumulated in the vacuoles of those cells, and the plant uses the resulting osmotic potential to take up water from saline soil. The species has been proposed as a salt-accumulating crop for saline agriculture, since the biomass can be harvested and removed, taking the salt with it.
Uses & Benefits
The leaves are edible, crisp and salty, and they are sold as a vegetable in Japan, where the plant is grown hydroponically and marketed as ice plant. In southern Europe the young leaves are used in salads, and the seed has been gathered as a famine food in South Africa. The plant is also used as a soap substitute in its native range, since the ash is rich in soda.
In a garden it is a plant for a hot, dry, salty corner, a gravel bed or a coastal garden, where its sparkling leaves and pink-white flowers are a novelty in summer. It is also used to cover bare ground quickly on poor soil. It should be watched in mild climates, since it self-sows freely and has become invasive in parts of California and the Mediterranean.
Growing from Seed
Sow in early spring at 18-22 °C on the surface of a gritty compost, and cover very lightly. The seed needs light and germinates in two to three weeks. The seedlings are tiny and should be kept on the dry side once they are up, since damping off is the main risk.
Plant out in full sun in poor, sharp-draining soil, and water sparingly; the plant grows best when it is stressed, and rich, wet ground produces soft, sprawling growth with few flowers. It needs no feeding. In a cold climate treat it as a half-hardy annual and collect seed in autumn, since it will not survive a frost.
Our Take
The plant that switches to CAM when it is stressed, and looks like frost in midsummer. Grow it on a hot, salty bank, and eat the leaves.
Related Reading
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