How to Grow Mesembryanthemum
'Harlequin' from Seed
The solar-tracking neon carpet -- a Half-Hardy Annual succulent from South African coastal deserts producing glistening ice-crystal leaves and neon flowers in shocking pink, electric orange, peachy apricot, and sunny yellow that open only in direct sunlight, tracking the sun across the sky; surface sow on gritty compost at 18-21°C; plant out June in the fullest sun available; do NOT overwater (true desert succulent); rockeries, gravel, walls, containers in the hottest driest spot
Mesembryanthemum 'Harlequin' (Dorotheanthus bellidiformis) -- the Livingstone Daisy or Ice Plant -- is nature's answer to the question "what grows in the place where nothing else will?" In the scorching coastal deserts of South Africa's Western Cape, where summer temperatures routinely exceed 35°C and months can pass without rain, the low, ground-hugging carpet of glistening, crystalline leaves produces flowers in colours so intense they almost appear artificially dyed. The "Harlequin" mix brings together neon shocking pinks, electric oranges, peachy apricots, and sunny yellows -- many with dramatic contrasting rings at the centre -- in a display that is genuinely unprecedented in brightness and saturation among hardy annuals available to UK gardeners.
Two characteristics make Mesembryanthemum unique in the cottage garden context. The first is the solar tracking behaviour: each flower is a heliotrope that opens wide in direct bright sunlight and tracks the sun's path across the sky during the day, closing tightly in the evening and on any cloudy or overcast day. This means the display depends entirely on sunshine -- on a dull UK summer day, the plant may appear to have no flowers at all, while on a bright summer day the same plant is a carpet of neon. The second characteristic is the ice-crystal leaf effect: the leaves are covered in transparent water-vesicle cells that catch light like scattered crystals, giving the whole plant a glistening, frosted appearance even before any flowers open.
Quick Facts at a Glance
Plant Type
Half-Hardy Annual H2 -- South African coastal desert succulent
Flowers
Neon shocking pink, electric orange, peachy apricot, sunny yellow; solar tracker
Opening
Flowers open in direct sun; CLOSE on cloudy days -- must be in fullest sun available
Watering
Do NOT overwater -- a true desert succulent; thrive-on-neglect once established
Position
Rockeries, gravel, walls, path edges, containers; the plant for the hottest driest spot
Difficulty
2 out of 5 -- need warmth to start; then genuine neglect is best
Understanding the Plant
The Solar Tracking Behaviour -- Choosing the Position
Mesembryanthemum flowers are obligate heliotropes -- they require direct, bright sunlight to open and will remain completely closed in shade, partial shade, or overcast conditions. This means two things for the gardener: first, choose the absolutely sunniest position available (a south-facing wall, a gravel bed in open sun, or the top of a dry stone wall in full sun -- not just "sunny"); second, observe the garden through the day to ensure the chosen position receives continuous direct sun from morning to late afternoon rather than dappled or intermittent sunlight. In the fullest sun, Mesembryanthemum is spectacular; in a position with even 2-3 hours of shade per day, the display period is dramatically shortened.
The Succulent -- Why Overwatering is Lethal
Dorotheanthus bellidiformis is a true succulent with water-storing tissue in both its leaves (the transparent water vesicle cells that create the ice-crystal appearance) and its stems. This tissue allows the plant to survive extended drought without any supplementary water by drawing on its reserves. Overwatering does not make the plant grow faster or flower more -- it causes root rot that kills the plant within days. Once established outdoors in the UK, this plant needs no supplementary watering except in the most extreme, prolonged drought conditions. In containers, allow the compost to dry out almost completely between waterings. In the ground, water once during establishment and then leave entirely alone.
Seed Germination -- Tiny Seeds, Correct Conditions
Mesembryanthemum seeds are among the finest and most dust-like of all seeds -- almost impossible to handle individually. Surface sowing onto moist, gritty compost is essential (the seeds require light to germinate). Keep the tray at 18-21°C in a bright position. Do not cover the tray tightly -- some air circulation prevents damping-off in the fine seedlings that are highly susceptible at the earliest stage. Germination 7-14 days. Prick out when seedlings have their first true leaves -- this is fiddly work with such small plants but important for individual development. Harden off thoroughly before planting out in June.
Sowing & Growing On
Surface Sow at 18-21°C -- Light Required -- Plant Out June in Full Sun -- Do Not Overwater
Surface sow tiny seeds on moist gritty compost at 18-21°C from Feb-April. Light required -- do not cover. Germination 7-14 days. Harden off and plant out in June only in the fullest available sun. Water once at establishment and then rely on natural rainfall and the plant's own succulent reserves.
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Surface sow indoors Feb-April at 18-21°C. Do not cover -- seeds require light. Scatter seeds thinly on moist, free-draining gritty seed compost (add 30% horticultural grit). Press gently to ensure seed-to-compost contact. Keep in a bright position at consistent warmth. Germination 7-14 days. Seedlings are tiny and delicate at first.
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Prick out into individual small pots when seedlings have their first true leaves. Handle by the seed leaf only -- the stems are fragile. Use very gritty compost (50:50 compost and horticultural grit). Grow on in maximum light at 18-20°C. Begin hardening off from late May -- these seedlings are less frost-tender than their tropical appearance suggests, tolerating temperatures to +5°C briefly.
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Plant out in June in the fullest available sun. Space 15cm apart. Rockeries, gravel gardens, path edges, dry stone wall tops, south-facing containers -- any position that receives maximum direct sun and has sharp drainage. Do not plant in partial shade or positions with intermittent sunlight. Water once at planting and then leave.
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Do not water once established. Do not feed. Mesembryanthemum thrives on neglect. Supplementary watering causes root rot. Feeding produces leafy growth at the expense of flowers. In containers, allow compost to dry almost completely between very occasional waterings. Watch the flowers track the sun on bright summer days and close on cloudy ones.
Growing On & Care
The Solar Display
On a bright, sunny summer day, a carpet of Harlequin Mesembryanthemum is among the most visually arresting sights in the cottage garden: the neon pinks, electric oranges, peachy apricots, and sunny yellows -- each with its contrasting ring at the centre -- open simultaneously to face the sun, creating a display of colour saturation that no other hardy annual matches. The individual flowers are 4-5cm across, flat, with narrow strap-like petals that radiate from the centre, and the contrasting ring that marks the boundary between inner and outer petal colour adds detail and depth to each individual bloom. On a dull day, exactly the same position appears to have no flowers at all -- the closed buds are inconspicuous. This solar dependency is part of the plant's character, not a failing.
The Ideal Positions -- Hot and Dry
Mesembryanthemum occupies the niche that almost nothing else can: the scorching, completely dry, south-facing positions that challenge even Mediterranean plants. The top of a dry stone wall in full sun (roots in the gritty mortar crevices), a rockery face with south aspect, the edge of a gravel driveway, a terracotta container with pure grit compost positioned against a white-washed wall -- these are not compromise positions but preferred positions for Mesembryanthemum. In these conditions, with the heat accumulation and rapid drainage they provide, the plant performs with more vigour, more continuous flowering, and more intensive colour than in any "better" growing conditions.
The Ice-Crystal Leaves
The transparent water-vesicle cells covering the leaves of Dorotheanthus bellidiformis create the distinctive glistening, frosted appearance that gives the plant its "Ice Plant" common name. Each cell is a balloon of water -- visible to the naked eye as a tiny transparent blister on the leaf surface. In direct sunlight, these vesicles catch and refract light, making the whole plant sparkle with a crystalline quality quite unlike any other garden plant. Even before flowering, a tray of Mesembryanthemum seedlings has this glistening quality -- it is the plant's characteristic and most immediately recognisable feature.
Heatwave Plant -- UK Climate Change Benefit
As UK summers become warmer and drier, Mesembryanthemum becomes increasingly relevant and increasingly reliable. The conditions that allow it to perform spectacularly -- prolonged sunshine, warm temperatures, dry spells -- are becoming more common in southern UK gardens. In the increasingly warm urban gardens of London, Bristol, and the south coast, Mesembryanthemum is now approaching the continuous, long-season performance of its native South African habitat. In a changing climate context, this is a plant to invest in and expand in the planting palette.
Pollinator Value in Heat
Mesembryanthemum provides a critical pollinator resource specifically during UK heatwaves -- when most other garden flowers wilt, close, or reduce their nectar production in extreme heat, the heat-loving Livingstone Daisy continues to open and provide accessible pollen and nectar. The wide, open flower structure with visible stamens and pistil is accessible to a range of bees, hoverflies, and butterflies. During July and August heat events, Mesembryanthemum can become the primary functioning pollinator plant in a garden where other species have temporarily closed or reduced their display.
Container Culture -- Maximising the Display
In a container with 50:50 compost and horticultural grit, positioned in the maximum available sun, Mesembryanthemum performs as a continuous June-September display that costs almost nothing in water and maintenance. Use a wide, shallow terracotta pan (30-40cm diameter, 15-20cm deep) rather than a deep pot -- the shallow root system suits shallow containers. Plant 5-7 seedlings per pan, 15cm apart. Position on a south-facing patio, balcony, or gravel surface in full sun. Water once on planting day and then only if the compost is completely dry and the plant shows obvious wilting -- rare in UK summers, even hot ones.
Sowing & Flowering Calendar
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| Flowers (Jun-Sep) |
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Common Problems & Solutions
| Problem | Likely Cause | What to Do |
|---|---|---|
| Flowers not opening | Insufficient sunlight; cloudy weather | This is normal behaviour -- flowers only open in direct sunlight. If the position receives adequate sun but flowers still fail to open, the plant may be in a position with intermittent rather than continuous direct sun (buildings casting afternoon shade, etc.). Move to a position with uninterrupted all-day sun. |
| Plant rotting, dying suddenly | Overwatering; waterlogged soil | Do not water once established. In containers, allow compost to dry almost completely between waterings. Ensure drainage holes are completely clear and unblocked. Root rot is the primary cause of Mesembryanthemum failure; it is always water-related. |
| Sparse flowering; leafy growth | Too much shade; over-fed soil | Move to a sunnier position. Do not feed -- feeding produces lush leafy growth at the expense of flowers. Mesembryanthemum performs best in lean, poor, gritty conditions that stress the plant into flowering rather than growing. |
| Seedlings damping off | Fungal disease; poor air circulation | Ensure seed trays are not covered too tightly during germination -- some air circulation reduces damping-off fungal risk. Use sterile, gritty seed compost. Remove any collapsed seedlings promptly to prevent spread. |
Plant Specifications
The neon solar carpet that glitters and glows in sunshine -- plant it in the hottest, driest spot and then ignore it
Surface sow on gritty compost at 18-21°C from February-April. Do not cover -- light needed. Plant out in June in the absolute fullest sun available. Water once on planting day. Then do nothing -- no watering, no feeding. When the sun comes out, the neon flowers open and track it across the sky. On cloudy days they close completely. This is the plant for the hottest, driest spot in the garden.
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