Being a lover of the hardier kinds of succulent, Sempervivum are certainly up there in my top 10. They are just as hardy as any Echeveria, Crassula or Agave succulent in my opinion. They can survive heat, drought, frost and general neglect and still look fabulous. In Europe their common name is House Leek, in the United States it is Hen & Chicks. Here are a few facts and pointers for the Sempervivum genus.
A member of the Crassulacae family Sempervivum are native to the mountains of central and southern Europe and can grow at 3000-8000 feet above sea level. There are about 50 different species. They vary in size, form and colour and grow in rosette formation. The name Sempervivum comes from the Latin words semper, meaning “always,” and vivus, meaning “living.” Which describes its everlasting nature. Pronounced: Semper Vee Vum.
Sempervivums come in many colours such as pink, orange, yellow, red, green and brown. To see its colour in full glory they need to grow in full sun. If not grown in full sun they will grow as green in colour. Mature plants can be from half an inch to 6 inches (1 to 15 cm) in diameter.
Even though Sempervivums are native to Europe which is not well known for its hot summers. Sempervivum cope, and dare I even say ‘love’, full sun. They do not need a lot of water and are drought tolerant. This is great news for hot Australian Summers, however I would be inclined to cover them if the temperature if forecast over 40C/104F as their leaves may get sun burnt. I would suggest that this would not kill the plant but probably just look a bit unsightly until the sun burnt leaves shrivel and drop off.
On the other side of the coin Sempervivum are one of the most frost resistant succulents. This would be due to their origins being in mountainous regions of Europe. They can survive in extremely cold temperatures, most will survive temperatures as low as -30F/-34C apparently.
Light and Water Requirements
Sempervivum can survive in full sun and tolerate drought conditions. They do not require a lot of water but can also survive a wet winter as long as they are growing in well drained soil or on a slope if grown in the garden. If grown in pots move them under the eaves of the house to avoid temperature fluctuations and avoid wet winters.
Some species of Sempervivum are…….. hairy. That is the only way to describe them. They have tiny white hairs growing along their leaves and also on the tip. This is the best way to distinguish a Sempervivum from any other rosette forming succulent. Only Sempervivum have these tiny hairs.
Sempervivum covered with cobwebs
Sempervivum Arachnoidium looks like it is covered in spiders webs. (see below). It is another amazing succulent. The cobweb starts off in the middle of the plant and eventually spreads to cover all leave in the rosette. It can then spread to cover the clump of Sempervivums.
Most Sempervivum are prolific at producing offsets which grow off the side of the parent plant and produce a large clump. However, some Sempervivum produce offsets on the end of long stems which are called ‘stolons’ these then set down roots at a distance from the parent plant. Once the roots have developed the plant can be grown independently from the parent plant.
Flowering – and the bad news
Flowers are shades of pink, red and sometimes yellow. If and when Sempervivum flower it happens in mid to late Summer. The bad news with regard to Sempervivum flowers is that Sempervivum succulents are monocarpic which means that the parent plant dies after flowering. It will shrivel and die. It can then be easily pulled out and this will allow room for the pups to spread. Sempervivums are perennials so they live for at least 3 years or more before they flower. Sempervivum flowers produce a star-shaped fruit containing seeds which can be collected and grown. See Post : Which succulents die after flowering?
In Europe Sempervivums were traditionally grown on roofs. They were thought to ward off evils spirits and raging storms. Below are a couple of examples from Pinterest. I assume they would need to be grown on a pitched roof for water to run off so as the roots are not sitting in water.
Being as hardy Sempervivum are they do not have many additional problems to deal with. Any succulent is prone to mealy bugs or powdery mildew and root rot from over watering.