Common houseleek

Common houseleek: how do you recognise it?

Habit

Rosettes 5–10 cm wide and 5–10 cm tall that together form a cushion; flower stems 20–30 cm.

Leaves

Fleshy, pointed and stiff, in tight rosettes; green, often with red-purple tips.

Flower

Starry flowers of 2–3 cm in a flat cluster on top of a thick, leafy stem, in July–August.

Colour

Pink to reddish purple.

Offsets

Young rosettes on short runners around the mother plant; the mother dies after flowering.

Flowering: July–August · Plants: March–September

Why grow it?

• Evergreen, decorative rosettes that look good all year round.
• Incredibly drought-tolerant: ideal for a rock garden, wall, roof, bowl or pot.
• Bees visit the pink, starry flowers in July and August.
• A tough ground cover for poor, stony places where little else grows.
• Almost no work: no pruning, no feeding and rarely any watering.

Common houseleek: where does it grow best?

• Full sun: in shade the rosettes turn green, open and stretched.
• Poor, very free-draining sandy or loamy soil, with gravel or grit; acid, neutral or chalky.
• Dry: standing water and wet soil make the rosettes rot.
• Plant 15–20 cm apart, between stones, in cracks, on a wall or in a bowl.

Light

Sun

Soil type

Sand or loam

Acidity

Not fussy

Moisture

Dry

Size

0.15 m tall, 0.3 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Stonecrop: Another tough succulent for the same poor, sunny spot.
• Creeping thyme: A fragrant carpet between the rosettes, also loved by bees.
• Blue fescue: Blue tufts as a contrast to the round rosettes.
• Saxifrage: Small cushions and rosettes for a rock garden or trough.

Common houseleek: when and how to plant it?

Plant in March–September.

1. Plant from March to September, when it is not freezing.
2. Mix ordinary soil with at least one third gravel or coarse sand; in a pot use cactus compost or potting compost with grit.
3. Set the rosette shallowly, with the lowest leaves just resting on the soil, never deeper.
4. Leave 15–20 cm between rosettes; the offsets will fill the gaps.
5. Water once, lightly, and spread gravel around the rosettes so they stay dry.

Care

Watering

Only after planting. In a pot, now and then during long droughts; never in winter.

Feeding

Never: fertiliser gives soft, stretched rosettes that rot more easily.

Dead rosettes

After flowering, twist out the withered flower stem with the dead rosette.

Repotting

Every 2–3 years in spring, when the pot is full; split off the offsets at the same time.

Weeding

Weed by hand between the rosettes so they do not get overgrown.

Tip: Plant in a mix of ordinary soil with at least one third gravel and never feed: the leaner the soil, the more compact and colourful the rosettes.

Common houseleek: when to prune it?

When: Houseleeks are not pruned. After flowering, in August–September, you do remove the dead rosettes.

How:

• After flowering, twist or cut out the withered flower stem together with the dead rosette.
• Let the offsets fill the gap or plant a few young rosettes there.
• Remove dead, rotting lower leaves after a wet spell.

Pruning calendar and basic rules

Propagation

Offsets

From March to September, detach a young rosette with its runner and press it shallowly into poor, gritty soil. It roots within a few weeks.

Loose rosettes

Even a rosette without roots will take if you set it on moist sand or gravel and do not keep it too wet.

Common houseleek: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: frost is no problem in Belgium.
• Wet is the biggest danger: choose a well-drained spot and clear fallen leaves off the rosettes.
• In a pot: choose one with a drainage hole and no saucer, and keep it out of the rain in winter.

Diseases and pests

• Rot: Rosettes turn brown, glassy and soft. The cause is wet soil or water in the rosette. Remove them and replant the rest in grittier soil.
• Vine weevil: Rosettes come loose and have no roots left: white grubs have eaten them. Remove the grubs and use nematodes.
• Birds: Blackbirds pull out rosettes while searching for insects. Press them back and add some gravel around them.
• Stretched rosettes: Green, open, tall rosettes caused by too little light or too much fertiliser. Move them to a sunnier, leaner spot.

Through the year

• March: Planting. Remove dead leaves.
• April: Planting. Take offsets. Repot.
• May: Planting. Take offsets.
• June: Planting. The flower stems appear.
• July: Flowering. Bees on the starry flowers.
• August: Flowering. Remove dead rosettes.
• September: Last planting month. Take offsets.
• October: Clear fallen leaves off the rosettes.
• November: Move pots out of the rain.
• December: Rest. No watering.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Sempervivum means ‘always living’ and tectorum ‘of the roofs’: it used to grow on thatched and slate roofs.
• Around the year 800, Charlemagne had it written into a decree that the gardener should have houseleek on his roof; folk belief held that the plant kept lightning away.
• Each rosette flowers only once and then dies, but the young rosettes around it take over.