Gadenin日本語Get the appThis is an outdoor plant, and that is not a compromise
Almost every succulent sold alongside sempervivum has to come indoors before the first frost. Houseleeks do not. They grow wild on mountain screes and rooftops across Europe, sitting under snow for months, and a plant that has hardened off outdoors takes 5F (minus 15C) without any protection at all. Many will take considerably lower. Bringing one inside for the winter is the single most common mistake made with this plant, and it produces a pale, stretched, floppy rosette by spring.
The corollary is that if your houseleek is in a windowsill pot in a heated room, it is not resting, it is slowly deteriorating. Move it outside. If it has spent months indoors, give it a fortnight in a bright, sheltered spot outdoors before putting it in full sun, because leaves grown in weak light scorch. Otherwise the move can be immediate, in any season other than the depths of a hard freeze.
Hardiness applies to a plant with dry roots. A sempervivum sitting in wet compost at 23F (minus 5C) can die when the same plant in gritty, free-draining mix is untouched. Cold is not the danger; cold plus water is.
How much sun the color needs
Sempervivum foliage color is a stress response. Red, purple, bronze and near-black tones develop when the plant gets strong light, cool nights and very little food or water. Give it comfort and it reverts to plain green. This is why a plant that looked spectacular in the nursery goes green within a season in a sheltered, well-fed position, and why growers who want color deliberately starve their plants.
The practical target is at least six hours of direct sun a day, and more is better. In hot climates with sustained days above 95F (35C) a little shade in the mid-afternoon prevents scorch marks on the broadest-leaved forms, but morning shade is never the answer: it costs you color without protecting anything.
| Position | What the plant does | Verdict |
|---|---|---|
| Open ground or a pot in full sun | Tight, low rosettes with strong color | Ideal in almost every climate |
| South or west wall, sun most of the day | Good color, fast offsetting, dries quickly after rain | Excellent, especially in wet climates |
| Light shade for part of the day | Larger, greener rosettes, slightly looser | Acceptable but the color goes |
| Full shade under a shrub or fence | Rosettes open out flat, leaves elongate, offsets on long stems | Move it. The plant is failing slowly |
| Indoors on a windowsill | Pale, stretched growth and eventual rot | Never a long-term position |
Shelter from rain, not from cold
The right position sheds water fast. That means an open spot where wind and sun dry the crown of each rosette within a few hours of rain, rather than a still corner where droplets sit in the center for a day. A rosette that stays wet in the middle at 40F (4C) is where rot starts, and by the time the center turns brown and pulls out at a touch, the plant is already gone.
In climates with a long, wet, mild winter, the risk is far higher than in a place with a dry, hard freeze. If your winters are gray and drizzly, tilt the pot slightly so water runs out of the rosettes, stand it on feet or gravel so the base is never in a saucer of water, and consider a pane of glass or an open-sided cover overhead from late autumn to early spring. Leave the sides open. The plant needs the air far more than it needs the warmth.
Where they look and grow best
Houseleeks are at their best in shallow, wide containers rather than deep ones, and in positions where the rosettes sit almost at eye level or above. Pans, alpine troughs, wall pockets, the crevices of a dry stone wall, gravel gardens, the gaps between paving and shallow trays on a flat roof all suit them. Their root system is small and fibrous and does not need depth. Two to three inches (5 to 8 cm) of gritty mix is enough to support a mature colony indefinitely.
In open ground, plant them on a slope, a raised bed, or a mound of grit rather than a flat border, and keep them clear of anything that overhangs and drips. Do not plant them near a lawn edge that gets watered, or under the eaves where a downpipe splashes. If a plant sits in a spot where a puddle forms after heavy rain, no other part of your care routine will save it.
What to note about position
Position is the variable most worth recording, because its effects show up a full year later. For each pot or patch, write down which compass direction it faces, roughly how many hours of direct sun it gets at midsummer, and whether it is covered in winter. Then, at the end of the following summer, note the color of the rosettes and whether they are tight or open.
Do the same for two or three different spots in the same garden with plants from the same batch, and within one season you will know exactly where your best color comes from. It is also worth noting the date of any move, because the fortnight of stretched, pale growth that follows a move out of shade is easy to misread as a pest or a disease if you have forgotten you moved the plant.