Mesembryanthemum is a drought tolerant, low-growing succulent that produces pretty daisy-like flowers in bright pastel colours all summer long. It's also called ice plant, as its stems and leaves are covered in small water-retaining structures that glisten in the sunshine, giving a frosted effect. It's also sometimes called Livingstone daisy (named after the explorer David Livingstone), but this is used for several similar plant groups.
Mesembryanthemum leaves, stems and seeds are edible. However, as a number of different plants have the same common name – ice plant –be absolutely sure which plant you have before you start harvesting and serving it up. Mesembryanthemum leaves and stems can be steamed like spinach and have a salty, sharp taste.
The flowers open in the sun and close at night to protect them from dropping temperatures or rain. While they are pretty, the orange centres of their flowers fringed with slender petals in pink, yellow, white or orange, mesembryanthemum are not attractive to UK pollinators such as bumblebees.
How to grow mesembryanthemum
Grow mesembryanthemum in full sun, in free-draining soil, ideally in a gravel garden or rock garden, between paving stones or in cavities in walls. They can also be grown in pots. Deadhead spent blooms to prolong flowering and trim to size in autumn if necessary. Most mesembryanthemums are grown as annual bedding plants and discarded in autumn, but in mild conditions they may survive winter, or you can dig up and overwinter them indoors, to replant out from late spring.
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Where to grow mesembryanthemum
Grow mesembryanthemum in full sun at the edge of a border, in a gravel garden or rock garden, between paving stones, in cavities in walls or in a container in full sun. In the right conditions it will spread to form a low dense mat of thick foliage that can be green or have a reddish tinge. A single plant can grow up to 50cm across in one season. It grows well in poor dry soil or rich soil, as long as it’s free draining. Avoid damp or waterlogged places, where the roots will rot.
How to plant mesembryanthemum
Mesembryanthemum originates in South Africa and its common name, ice plant, is misleading – it doesn’t survive frost or freezing temperatures. In the UK it will overwinter outside in very sheltered gardens or on the south coast, but otherwise wait until all danger of frost has passed before you plant it out. If you’re going to grow it in a container, you could plant it earlier and keep it indoors somewhere where it will get lots of light, like a sunny frost-free greenhouse or conservatory, or on a sunny windowsill until late spring.
Use a trowel to dig a hole just big enough to take the root ball of your plant, back fill and firm around the plant, making sure its base is level or slightly higher than the surrounding soil. Give it a good water, soaking right down to the roots and then water it regularly for the first couple of weeks while it establishes. If you are planting more than one ice plant, space them out at 15-20cm intervals.
How to care for mesembryanthemum
Mesembryanthemum is perennial, but because it’s not frost hardy, it's widely grown as an annual bedding plant. Apart from keeping it well watered for a few weeks after planting in late spring, this plant needs little care. If growing it in a container, allow the compost to dry out completely between watering.
How to prune mesembryanthemum
To keep the cheerful display going all summer and into autumn, deadhead the old flowers by pinching or cutting them off. It's easy to limit the spread of the plant by cutting the stems, either with secateurs or using a spade. If you're overwintering your ice plant indoors, prepare it in autumn by using shears to trim off any remaining flower heads and cut the foliage to a uniform height.
How to propagate mesembryanthemum
Mesembryanthemum can be grown from seed sown indoors in a free-draining compost in late winter or early spring. They need indirect light to germinate, so don’t cover the seed and keep the compost moist at 16-19ºC. The seed should germinate within two weeks. You can multiply your mesembryanthemum by cuttings, too. In early summer, locate stems without flower buds, and use a sharp knife or secateurs to take 5-10cm long sections, remove the lower leaves and insert into free draining compost or river sand. Keep the substrate moist until the cuttings root. You can also put the cuttings in water, and pot them on once roots have appeared.
Pests and diseases
Mesembryanthemum isn’t troubled by pests or diseases when grown outside, but it may attract aphids (greenfly) indoors. These can be removed by hand. If the foliage becomes yellow and the soggy, the ground is too wet for it.
Advice on buying mesembryanthemum
- As they are commonly grown as annual bedding plants, you’ll be able to buy mesembryanthemum as plug plants or packs of mixed plants in garden and plant centres in spring and early summer
- The foliage should be plump, not shrivelled, and strongly coloured, not yellow. Check between the leaves for aphids