<em>Delosperma</em>, perennial ice plant: planting and growing

Description and botany

Delosperma, perennial ice plant or perennial ficoid, is a succulent plant in 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 a dozen are offered in cultivation. Delosperma cooperi or Cooper’s ice plant is best known and most widely grown.

Very often seen are Delosperma hybrids from new ‘Wheels of Wonder’ series, remarkable for their flowers twice the size of the species, available in a range of six bright, radiant colours. Less frequently encountered are Delosperma crassuloides with white flowers or Delosperma echinatum, two tender species best reserved for Mediterranean climates.

Delosperma forms a small, low tuft with an erect or prostrate, even trailing habit, rarely exceeding 10 to 15 cm in height. Its very brittle stems root and ramify easily on contact with soil to extend year by year, quickly carpeting an area up to 1 m wide when conditions suit. It develops into a very dense groundcover and can remain in place for many years.

Its succulent foliage clustered on creeping stems is evergreen. Sessile, very fleshy and pointed, the leaves measure from 0.5 to 5 cm long, are triangular to cylindrical and appear in opposite pairs. Epidermis is verrucate, covered with tiny papillae that protect it from strong sun. These succulent leaves store water and serve as the plant’s reserve. They display every shade of green, from pale to glaucous bluish, some showing white highlights, hence English nickname “Ice Plant”.

Delosperma cooperi – botanical illustration

Delosperma produces an abundant, bright and very colourful display from June until first frosts. Star-shaped flowers 0.5 to 5 cm in diameter, in solitary heads or grouped in cymes at each stem tip, spectacularly enliven the foliage and can almost completely cover plants, especially in ‘Wheels of Wonder’ series, which bear flowers twice the size of the species.

Corollas resembling daisies 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 luminous orange, colours are so vivid and bright they seem 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

Flowers open at sunrise and close in the evening at dusk. Generous, they renew until early autumn, attracting butterflies to your garden.

Half-hardy, perennial ice plant is best suited to Mediterranean climates, coastal gardens and mild regions where severe frosts do not occur. In cold, harsh or wet-winter areas, it is preferable to grow it in tubs or pots and bring indoors to a conservatory for winter protection, 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, even dry, rocky soil, including sandy seaside soils. From its origins it retains very good drought tolerance.

Plant in edge of dry border, in rockery, in pots, window boxes or on a well-exposed bank.

Main species and varieties

Most popular

Our favourites

Delosperma cooperi

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

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

See the product sheet

Delosperma Wheels of Wonder Golden - Ice Plant

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

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

See the product sheet

Delosperma Wheels of Wonder Hot Pink - Ice Plant

A new hybrid delosperma notable for its large flowers in bright colours. Plant above low walls, in rockeries or in pots to ornament a terrace.

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

See the product sheet

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. An outstanding rockery plant that will also perform well in a container.

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

See the product sheet

Ice Plant Stardust Seeds - Delosperma floribundum

We love its long flowering of blue-and-white stars. Use in rockeries, pots or in well-exposed planters.

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

See the product sheet

Planting

Where to plant Delosperma or perennial purslane

It is a plant of warm, dry climate. Delosperma or perennial purslane has fairly average hardiness (it 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 harsh.

Some species that are truly tender (Delosperma echinatum) struggle with temperatures below 0°C and will only be grown in gardens of southern France. In cold and especially humid climate, it is preferable to grow it in a pot to shelter in winter under a conservatory and put back out in fine weather.

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

It requires full sun and heat to flower well in very well-drained, rather poor, dry, even stony soil: it is the dry rock-garden plant par excellence that adapts perfectly to poor soils and grows provided it finds a little substrate. It does well in sandy soils. Conversely, heavy, waterlogged soils and freezing winter rains are fatal.

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

When to plant Delosperma or perennial purslane

Plant 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 intense drought.

How to plant Delospermas or perennial purslanes

In ground

Allow around 5 to 6 plants per square metre, spaced 30 cm apart for a beautiful tapetum in flower with succulent leaves.

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

• Soak rootball before planting
• Dig a hole 2 to 3 times wider than the bucket
• Remove plant from bucket and place rootball
• Backfill, adding a little river sand to garden soil
• Firm down lightly
• Water during establishment

In a pot

Substrate must be light and very free-draining to avoid stagnant moisture at roots. Place Delosperma in full sun in a pot at least 30 cm in diameter.

• Spread a good drainage layer (gravel or clay pebbles)
• Plant in a mix of potting compost, garden soil and gravel
• Shelter it from frost and winter rains by bringing it into 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 done in seed tray in March or in April–May outdoors.

In seed tray

• At temperature of 18–21 °C, sow thinly in seed tray on moist potting compost
• Do not cover seeds and place in light, keeping moist until germination which takes 10–21 days
• As soon as seedlings are sturdy enough, prick out into 7 cm buckets
• Plant in May outdoors, spacing plants about 25 cm once risk of frost has passed, or in pots or planters

Outdoors

• Sow perennial ice plant seeds thinly (broadcast) in lightened soil mixed with coarse sand
• Cover with a thin layer of potting compost
• Firm gently
• Water
• Thin seedlings to leave 25 cm between plants

Maintenance, pruning and care of Delosperma

Hardly demanding, perennial ice plant grows unaided with no maintenance, braving drought provided conditions suit it: a sunny spot in well-draining soil with no stagnant water at its base. Once established, Delosperma is resistant to disease because it only fears excess water.

It is a succulent plant able to store large quantities of water.

Water only during first year following planting; once well established, it will live on rainwater, ideal in a garden with no irrigation!

Remove faded flowers to encourage their renewal.

In autumn, prevent the base from becoming covered with dead leaves, which could cause its foliage, very sensitive to excess water, to rot.

Every 2 to 3 years, in spring or autumn, divide the stump to regenerate the base.

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

Delosperma Wheels of Wonder Hot Pink

When and how to prune delosperma

Perennial ice plant is a groundcover that can be invasive at times. No pruning is really necessary; the only constraint may be to limit its growth by removing layering roots in early spring: cut them with pruning shears.

Remove any parts damaged by rain.

Multiplication

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

Propagation by cuttings of Delosperma

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

Uses and companion planting in the garden

Perennial ice plant is indispensable in rockeries of dry gardens, in holiday gardens without watering where it forms flowering, colourful tapetum.

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

Planted in mass, it provides contrast with its vibrant hues, in monochrome or multicoloured forms.

It is easy to combine with plants sharing the same needs: sun and dry soil.

On the edge of a sunny bed, it is perfect with a few achilleas, at the base of valerians, poppies or helianthemums. In the edge of a mineral bed, it will add a little touch of colour, slipped 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 ground-covering and undemanding perennials ideal for covering large areas on poor, dry ground such as mouse ears, Sedums, Dianthus, wall campanulas and Stachys.

→ Discover more ideas for combining Delosperma in our advice sheet!