Sempervivum MONTANUM

Sempervivum MONTANUM - Mountain houseleek, Sempervivum montanum.

Sempervivum numbers up to sixty species, commonly known as "houseleek, stone rose, liveforever". The name derives from the Latin words "semper" - always and "vivus" - living, for the ability of the leaf rosettes to maintain vitality under extreme living conditions. These plants are called stone roses not only for the flower-like shape of their rosettes, but also for their ability to survive in the harshest conditions. When flowering, the houseleek resembles a mother hen surrounded by numerous chicks. This gave rise to its popular English name "Hens and Chicks" - "mother hen and chicks".

It is difficult to imagine another plant that combines such vivid beauty with extraordinary unpretentiousness and Spartan endurance. Scree slopes and rock crevices, sandy or clayey soil, and often an almost complete lack of soil, scorching sun, and periodic water shortages are all quite comfortable for them (largely because this perennial is a succulent). Thanks to these qualities, houseleek is ideally suited for alpine rockeries, an essential feature of modern landscape design. Add to this its vegetative proliferation and exotic appearance (many look like cacti), and consider that it can overwinter under snow at -30 °C (-22 °F), and it becomes clear why these plants attract thousands of enthusiasts worldwide. In recent years, enthusiasts of this genus have also emerged locally. Hopefully, this will not be limited to mechanical collection building, but will stimulate domestic breeding of these plants.

Mountain houseleek is an evergreen succulent perennial forming dense, semi-open or open, oblate rosettes 1.5-3.5 cm (0.6-1.4 in) in diameter. The plant spreads quickly, forming dense carpet-like mats of offset rosettes. Offsets are very numerous, produced on slender, leafy, pubescent stolons 1-3 cm (0.4-1.2 in) long. The leaves are about 1-1.5 cm (0.4-0.6 in) long and 0.3-0.5 cm (0.1-0.2 in) wide, oblanceolate or oblong, acute, very fleshy, finely pubescent, dull, deep green, solid-colored or with reddish-brown tips, rarely also with a marginal border. Stem leaves are ovate, acute, sessile, pubescent, with reddish-brown tips or colored almost to the middle of the blade. Peduncles are 10-15 cm (4-6 in) tall, erect, finely pubescent, and leafy.

The inflorescences are relatively large, dense, corymbose cymes. Flowers number 3-10, measure 2-3 cm (0.8-1.2 in) in diameter on short pedicels, and are bright, reddish-purple or reddish-violet, star-shaped. Petals number 10-15, linear-lanceolate, subulate-pointed, glandular-pubescent beneath. Stamens number 20-30, with red filaments broadened at the base and yellow anthers. It blooms in July-August. Cold-hardy down to -29 °C (-20 °F). In nature, it grows in the mountains of Central Europe at an elevation of 1,500-3,400 m (4,900-11,200 ft). In cultivation since 1752.

Seeds are sown on the surface and lightly dusted with a thin layer of soil no thicker than 1 mm (0.04 in). Moisten with a spray bottle, cover with film, and germinate in the light at a temperature of 20-24 °C (68-75 °F). Seedlings require ventilation. It is essential to avoid waterlogging and drying out of the sowings. Seedlings emerge in 3-5 days.

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The plants are well adapted to unstable climates. They are quite hardy in cultivation and require no measures against excess moisture other than good drainage. The most sensitive to dampness is the heavily cobwebbed Sempervivum arachnoideum. All species and cultivars are drought-resistant. Shading, including by weeds or fallen leaves, is detrimental to them. Of course, they do not die immediately when overgrown, but they stretch, losing their compact form and vibrant coloration. Care consists of timely removal of weeds and spent inflorescences along with the withered leaf rosette.

In soggy soil, the lower leaves in the rosette begin to rot. This is the first sign of excess moisture. Every 3-5 years, if the clumps become overcrowded and rosettes begin to shrink, houseleeks are divided and replanted. Houseleeks are not endlessly drought-tolerant after all, especially if grown in poor soils. They do not perish, but they curl their rosettes and lose ornamental appeal. They develop well on any cultivated soils while avoiding waterlogged ones. However, dry, poor, sandy soils are preferred. If the soil is rich in nutrients, the plant will form larger rosettes, but their color will be paler than usual and they will be less cold-hardy for overwintering. Soils for all species should ideally be neutral or slightly alkaline. Coarse sand, expanded clay, and granite grit are used for aeration. Plants are spaced 10-15 cm (4-6 in) apart for large species and 3-5 cm (1.2-2.0 in) for small ones. Within a year, offset rosettes will completely cover the soil surface.