Sempervivums is a genus of about 40 species and 3,000 named cultivars of flowering plants in the Crassulaceae family, commonly known as houseleeks. 

Their name means always (semper) living (vivum) because of their remarkable ability to grow in barren places. Their common name, houseleeks comes from an old practice of growing them between roof tiles to keep the tiles in place.

Sempervivums are easy to grow tough succulent plants that can withstand dry summers and winters of freezing rain, as long as they have good drainage. This makes them ideal plants to grow in pots and containers, as ground cover in very dry places, in nooks and crannies in bricks and stone walls, or as a substitute for sedums on rooftops. 

When planting in pots make sure the potting mix is free draining – add up to 50 per cent grit or sand to multipurpose compost and top dress with more grit.

Thurrock Gazette: gardening

Sempervivums are made up of clusters of tightly packed leaves in shades of greens greys and reds with different coloured markings. 
They produce numerous offsets clustered around the mother plant, which can be removed to create new plants. 

Flowers are produced on tall stems above the plants mostly star shaped in shades of pink, however, the only downside is that the plant is monocarpic, so once it has flowered it dies.
However by the time it flowers you should have many offsets to replace it with. 

Once dead, remove the dead part and fill the space with grit and the space will soon be filled.

There are thousands of cultivars, however a few of my favourite varieties are S. Mrs Guiseppe, which has brown triangular markings on the tips of the green leaves, S. Red Devil, which has deep red large leaves that colour even more intensely in full sun. 

S. Cantabricum Picos de Europa has small rosettes of tightly packed bright green leaves backed and tipped in bright red, and finally S. Euphemia with deep red leaves tipped bright green and white hairs running between the leaf tips resembling a spiders web which is an adaptation to help reduce water loss from the leaves.

Thurrock Gazette: gardening

A large selection of sempervivums can be seen growing in the gardens and in the nursery at Green Island.
For further information visit www.greenislandgardens.co.uk