Mesembryanthemum crystallinum

Growing in Pots, Balconies & Indoors

Mesembryanthemum crystallinum (common ice plant) is a spreading, sun-loving iceplant grown as a ground cover – not a houseplant, since it needs full sun that indoor light cannot match. It is, though, a wonderful pot, trough and hanging-basket plant for a hot, open balcony or patio, where it trails and flowers freely. It is a short-lived perennial that is usually grown as an annual where winters are cold.

Quick Details

• Container Size: A wide, free-draining pot, trough or basket about 30% wider than the root ball; it spreads to fill whatever it is given (10-20 cm / 4-8 in, spreading)
• Indoor Suitability: Not a houseplant – it needs full outdoor sun; only the very brightest, sunniest windowsill would do, and even then it sulks
• Best Spot: Full sun (part shade at most) – the hotter and brighter, the better the flowering
• Soil & Drainage: Sandy or gritty free-draining mix; strong drainage holes
• Watering in Pots: Small amounts – very drought-tolerant; let it dry out and never leave it waterlogged

Indoors & On the Windowsill

• Not for indoors: The grower marks this as not a houseplant – it will not thrive indoors because it needs full sun to stay compact and to flower; in a room it stretches and stops blooming.
• Sunniest sill only: If you must try it inside, only the brightest, most direct-sun windowsill has any chance – it is really an outdoor plant.
• Overwintering: Usually grown as an annual in cold climates – there is little point overwintering it indoors; simply resow or take cuttings.

On a Balcony or Patio

• Full sun & trailing: This is its ideal home – give it the sunniest, most open spot and let it spill over the edge of a raised pot or hanging basket.
• Heat & watering: It loves the reflected heat from walls and paving; pots dry fast but it is very drought-tolerant, so water only when the mix has dried and never leave it waterlogged.
• Vigour: It self-seeds and spreads readily, so a container keeps it in bounds.
• Edible bonus: The succulent, crystalline leaves of this species are edible – a novelty crop for a sunny balcony.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: Choose a pot only about 30% wider than the root ball – an oversized pot holds wet soil around the roots. Rather than starting big, pot up every few years as it fills out; the mix loses structure over time, though a sharp, sandy mix that never sits wet can go five years or more between changes. Use strong drainage holes and skip a standing water saucer to avoid root rot.
• Pot material: Terracotta breathes and dries fast, which suits these rot-prone succulents; glazed or plastic pots hold moisture longer, so water even more sparingly.
• Potting mix: A gritty, free-draining mix – sandy or cactus/succulent mix, or peat/coir with perlite, with coarse lava grit at the base.
• Feeding: Feed only lightly – a dilute low-strength feed once or so during active growth, as frequent watering leaches nutrients from pots faster than from open ground.
• Watch for rot: Overwatering is the one real danger – in a rainy spot stand the pot in lava grit so water drains straight through, and always let the mix dry before watering again.

Bloom & Flower Guide

Quick Details

• Bloom Season: Winter, spring and summer
• Time to First Bloom: Usually in the first year, once established in a sunny, well-drained spot
• Flower Appearance: Small, flat, many-petalled white flowers
• Edibility: The succulent leaves are edible, but the small white flowers are grown for show, not for eating

Detailed Blooming Overview

The common ice plant is instantly recognisable for the glistening, water-filled bladder cells that coat its leaves and stems like frost. Its flowers are more modest — small, white, many-petalled blooms that appear across winter, spring and summer and open in sun. While the fleshy leaves are edible and sometimes eaten as a vegetable, the plant is grown here mainly for its crystalline look, and the flowers themselves are ornamental.

Flower Characteristics

• Small, flat, many-petalled flowers.
• White.
• Open in bright sun, close in dull weather and at night.

Bloom Care & Thinning

• Encouraging bloom: Full sun and sharp drainage bring the best flowering; shade and wet soil hold blooming back.
• Managing the bloom: A light trim after a flush keeps the plant tidy; leave some flowers if you want it to set seed.

Bloom Health & Protection

• Aphids often gather on the soft buds and new growth; a strong jet of water or a little insecticidal soap keeps them in check.
• In cool, damp spells gray mould (Botrytis) can spot the open flowers — improving airflow and removing faded blooms helps prevent it.