Delosperma, perennial ice plant: planting and growing

Description and botany

Delosperma, perennial ice plant or perennial ficoid, is a succulent plant belonging to family Aizoaceae, native to rocky cliffs and broken plains of South Africa, East Africa and Madagascar. Genus includes more than 150 species of bushes and mat-forming perennials but fewer than ten are commonly offered in cultivation. Delosperma cooperi, or Cooper’s ice plant, is best known and most widespread species.

You will often encounter the Delosperma hybrids of the new ‘Wheels of Wonder’ series, notable for their flowers twice the size of the type, available in a range of six vivid, radiant colours. Less frequently seen are Delosperma crassuloides with white flowers or Delosperma echinatum, two tender species best reserved for Mediterranean climates.

Delosperma forms a small low clump with erect, prostrate or even trailing habit, not exceeding 10 to 15 cm in height. Its very brittle stems root and ramify easily on contact with soil to spread year after year, quickly carpeting an area up to 1 m wide if conditions suit. It develops into a very dense groundcover and can remain in place for many years.

Its succulent foliage clustered on these creeping stems is evergreen. Sessile, very fleshy and pointed, the leaves measure 0.5 to 5 cm long, are triangular to cylindrical and appear in opposite pairs. Their epidermis is verrucate, covered with minute papillae that protect it from scorching sun. Its succulent leaves store water and act as reserves for the plant. They occur in every shade of green, from pale to glaucous bluish-green, and some show white highlights, hence English nickname ‘Ice Plant’.

Delosperma cooperi – botanical illustration

Delosperma produces an abundant, bright and very colourful display that lasts from June until the frosts. Star-shaped flowers 0.5 to 5 cm in diameter, in solitary heads or gathered in fairly loose cymes at the tips of the stems, strew the foliage so spectacularly that they almost entirely cover it, especially in the ‘Wheels of Wonder’ series, which bears flowers twice the size of the type.

The corollas, daisy-like, are formed of numerous fine, shiny ligules radiating around a golden-yellow, white or pink centre that contains a multitude of stamens. Pure golden-yellow, mauve, lilac, carmine red, white or bright orange, the colours are so vivid and striking they look painted and are visible from a distance. Some are bicoloured.

Several flower colours: Delosperma Wheels of Wonder Hot Pink, Delosperma Wheels of Wonder White, Delosperma Wheels of Wonder Fire, Delosperma Wheels of Wonder Golden

They open at sunrise and close again at dusk. Free-flowering, they continue until early autumn, attracting butterflies to your garden.

Half-hardy, the perennial ice plant is best suited to Mediterranean climates, coastal gardens and mild regions where severe frosts do not occur. In cold climates and regions with harsh, wet winters, it is preferable to grow it in tubs or pots and move indoors to a frost-free conservatory or greenhouse for winter, if temperatures fall below -8°C to -10°C.

Succulent foliage of Delosperma (photo Charlie Gaddy-Flickr)

To thrive, it needs a very sunny position in very well-drained soil, even dry, rocky ground, and tolerates sandy seaside soils. From its origins it has retained very good drought resistance.

Plant at edge of a dry border, in a rock garden, in pots or planters, or on a well-exposed bank.

Main species and varieties

Most popular

Our favourites

Delosperma cooperi

With its numerous mauve flowers, it is the best-known species and most used as groundcover. Ideal for covering low walls, filling rockeries or hanging baskets.

• Flowering time July to October
• Height at maturity 10 cm

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Delosperma Wheels of Wonder Golden - Ice Plant

A variety from Japan, selected at the Innovert 2014 competition of Salon du Végétal. Easily establishes between stones, on paving slabs of a path or on a dry bank.

• Flowering time July to October
• Height at maturity 15 cm

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Delosperma Wheels of Wonder Hot Pink - Ice Plant

A new hybrid delosperma notable for its large flowers with brilliant colouring. Plant above low walls, in rockeries, or in pots to decorate a terrace.

• Flowering time July to October
• Height at maturity 15 cm

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Delosperma Wheels of Wonder Orange - Ice Plant

One of six varieties in the 'Wheels of Wonder' series, notable for vigorous, floriferous plants with larger, brilliantly coloured flowers. A rockery plant par excellence, but will also thrive in a container.

• Flowering time July to October
• Height at maturity 15 cm

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Ice Plant Stardust Seeds - Delosperma floribundum

We love its long flowering of blue-and-white star-shaped flowers. Use in rockeries, pots, or well-exposed window boxes.

• Flowering time June to November
• Height at maturity 15 cm

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Planting

Where to plant Delosperma?

Delosperma or perennial purslane is a plant of warm, dry climate. The Delosperma or perennial purslane has fairly moderate hardiness (tolerates frosts down to -8 to -10°C in very well-drained soil), so planting is best reserved for regions where winters are not too severe.

Some species are very tender (Delosperma echinatum) and cope poorly with temperatures below 0°C, so they can only be grown in gardens of southern France. In cold, especially damp, grow it preferably in a pot, sheltering it over winter in a conservatory and bringing it out in spring.

Resistant to drought, wind and sea spray, it is a perennial well adapted to Mediterranean climate and coastal gardens.

It needs full sun and warmth to flower well in very well-drained, rather poor, dry, even stony soil: it is the dry rock-garden plant par excellence, perfectly suited to poor soils and growing as long as it finds a little substrate. It does well in sandy soils. Conversely, heavy, waterlogged soils and winter freezing rains are fatal.

It is indispensable as groundcover in seaside and dry gardens, in arid rockeries, between stones, on paving slabs of a path, on a bank, above a low wall or even in a trough, a hanging basket or a pot to bring indoors for winter, if necessary.

When to plant Delosperma or perennial purslane?

Plant the perennial purslane in spring, from February to April so it has time to root well before winter, or from August to October outside periods of frost or severe drought.

How to plant Delospermas or perennial purslanes?

In open ground

Allow about 5 to 6 young plants per square metre, spaced 30 cm apart for a beautiful tapetum of flowers with succulent leaves.

In heavy soil, add coarse sand or gravel to bottom of hole to improve drainage.

• Soak the rootball before planting
• Dig a hole 2 to 3 times wider than the bucket
• Remove from bucket and position the rootball
• Backfill, adding a little river sand to garden soil
• Firm lightly
• Water until established

In a pot

Substrate must be light and very well drained to avoid stagnant moisture around roots. Install Delosperma in full sun in a pot at least 30 cm in diameter.

• Lay a good drainage layer (gravel or clay balls)
• Plant in a mix of potting compost, garden soil and gravel
• Shelter from frost and winter rains by keeping in a greenhouse
• Water regularly but sparingly

→ Learn more about growing Delosperma in a pot

When and how to sow perennial purslane seeds?

Sowing of Delosperma or ice plant seeds is carried out in seed trays in March or outdoors in April–May.

In seed trays

• At 18–21 °C, sow thinly on surface of moist compost in a seed tray
• Do not cover seeds and place in light, keeping moist until germination, which takes 10–21 days
• As soon as seedlings are sturdy enough, pot on into 7 cm buckets
• Plant in May in open ground, spacing young plants about 25 cm apart once risk of frost has passed, or in pots or window boxes

Outdoors

• Sow the perennial ice plant seeds by broadcasting on light soil amended with coarse sand
• Cover with a thin layer of compost
• Firm down
• Water
• Thin seedlings to leave about 25 cm between young plants

Care of Delosperma

Undemanding, perennial ice plant grows unaided without maintenance, braving drought provided conditions suit: a sunny spot in well-draining soil with no standing water at its base. Once established, Delosperma is disease-resistant as it is only troubled by excess moisture.

It is a succulent capable of storing large amounts of water.

Water only during first year after planting; once established, it will rely on rain, perfect for a no-watering garden!

Remove faded flowers to encourage renewal.

In autumn, prevent plant from being covered by dead leaves, which could cause its foliage — very sensitive to excess moisture — to rot.

Every 2 to 3 years, in spring or autumn, divide the stump to rejuvenate the plant.

In a pot, water only once a week, keep dry in winter. Optionally apply liquid fertiliser in spring to encourage abundant flowering.

Delosperma Wheels of Wonder Hot Pink

When and how to prune delosperma?

The perennial ice plant is a groundcover that can be invasive. No pruning is really necessary; the only constraint may be to limit its spread by removing layering roots in early spring: cut them with pruning shear.

Remove any parts damaged by rain.

Multiplication

If sowing is possible, the easiest option is to take stem cuttings in summer. Division is also possible in autumn but more delicate because of fragility of Delosperma stems.

Propagation by cuttings of Delosperma

• Between July and September, take a stem with adventive roots
• Leave it to dry for a day or two
• Plant in small pots half-filled with garden soil and sand and a little compost
• Cover with sand
• Firm down
• Water cuttings regularly
• Overwinter them frost-free under cold frame
• Plant out into open ground the following spring when soil is well warmed and all risk of frost has passed

Uses and companion planting in the garden

Perennial purslane is indispensable in dry rockeries and in holiday gardens without irrigation, where it forms colourful flowering tapetum.

Delosperma ‘Kelaidis’ in dry garden (photo cultivar413-Flickr)

When planted en masse, it provides contrast with its vibrant hues, in monochrome or variegated form.

Easy to combine with plants sharing same needs: sun and dry soil.

At edge of a sunny border, perfect in company of a few yarrows, at base of valerians, poppies or helianthemums. At edge of a mineral bed, it will add a small touch of colour, tucked among grasses.

An idea for a pairing in a sunny, dry situation: Delosperma cooperi, Thymus serpyllum ‘Minimus’ and Artemisia canescens (photo Peganum)

In a dry rockery, it thrives alongside other undemanding groundcover perennials ideal for covering large areas on poor, dry ground such as mouse ears, Sedums, Dianthus, wall bellflowers and Stachys.

→ Discover more ideas for pairing with Delosperma in our advice sheet!