The Androsace genus (rock jasmine), particularly the Douglasia group, occupies a special place within the primrose family, as its members hail not from the high mountains of Europe or Asia, but from the alpine regions of the north-western United States—the Rocky Mountains and the Cascade Range. This group was formerly regarded as a separate genus (Douglasia) in botanical literature, but today it is classified under the genus Androsace. The best-known representative of the group is Androsace laevigata (formerly Douglasia laevigata), which, with its beautiful pink blooms and glossy, dark green leaves, is one of the most attractive figures among rock garden plants.
Androsace laevigata – The glossy-leaved rock jasmine
Androsace laevigata is a native of the high mountains of north-western USA, where it grows in rocky alpine meadows and crevices. It was only introduced to Europe in the second half of the twentieth century, and ever since, it has remained a rare but highly treasured feature of specialist rock gardens.
Appearance
The plant reaches a height of 5 cm and forms compact leaf rosettes. The leaves are dark green, leathery, 1–1.5 cm long, glossy, and narrow, terminating in a sharply pointed tip. This glossy, almost lacquered surface is not only decorative but also functional: it helps the plant reflect excessive UV rays and reduces evaporation.
In May, magenta flowers bloom, arranged in umbels of 2 to 5 flowers on stems 3–4 cm tall. The colour of the flowers is intense, vibrant and almost radiant – it is this shade that means, once seen, the plant is never forgotten.
Varieties
There are several varieties of Androsace laevigata, all of which are beautiful:
- Androsace laevigata var. laevigata – the original form, featuring glossy leaves and purplish-pink flowers
- Androsace laevigata var. ciliolata – fine hairs (ciliolae) adorn the edges of the leaves, lending an even more refined appearance
Both varieties are silicate plants, meaning they prefer acidic or neutral rocks and do not tolerate limestone soils.
Growing Location and Soil
As a silicate plant, it is best cultivated in andesite tuff, basalt stones, or granite. The soil mix should be acidic or neutral, and should include basalt flour. A good base mix might be: 1 part acidic leaf compost or pine bark compost, 3 parts fine andesite or basalt gravel (2–5 mm), 1 part basalt flour, and 1 part coarse sand or perlite. The pH should be between 5.5 and 6.5.
It thrives best in a bright, but not hot spot – ideally, an east- or north-facing rock wall, where it receives morning sunlight but is shaded in the afternoon. A humid environment is essential: regularly mist the surrounding stones and soil, but never water the plant itself directly.
In the USA, it is often referred to as ‘Cliff Douglasia’, indicating that in nature it grows in the crevices of vertical rock faces.
Care
Androsace laevigata is not a plant for beginners. It requires patience, care, and a precise soil mix. Because of its need for silicate, it is not compatible with rock garden plants that favour limestone—it is best grown separately, in a shallow depression made of acidic rock or in a tufa stone block.
In winter, it is important that the cushion does not become too wet—the combination of winter moisture and frost can cause rot. Protect it from winter precipitation, but do not let it dry out completely.
Companion plants
They make excellent companions for other silicate-loving alpine plants, such as:
- Saxifraga oppositifolia (purple saxifrage) – with similar needs and beautiful purple flowers
- Primula marginata (silver-edged primrose) – also favouring acidic soil, with silvery leaves
- Dianthus alpinus (alpine pink) – with vivid pink flowers, thriving in neutral to acidic soil
- Gentiana acaulis (stemless gentian) – with deep blue flowers, flourishing in acidic soil
These companions not only share similar soil preferences but also complement each other beautifully in colour: cyclamen, purple, blue and pink flowers create a wonderful harmony among the rocks of the rock garden.
The Douglasia group’s rockfoil – especially Androsace laevigata – are true jewels of New World alpine flora. With their striking pink flowers, glossy dark green leaves and compact habit, they bring unique beauty to the rock garden.
Key information:
- Silicate plant – can be cultivated in andesite tuff or basalt stones; avoids lime
- Acidic to neutral soil – a well-draining, gravelly mix with basalt flour
- Bright yet cool location – east or north facing
- Humid environment – mist the stones, do not water the cushion
- For more experienced gardeners – not for beginners
Androsace laevigata is a rare and prized plant, presenting a unique challenge, but those who succeed in cultivating it are rewarded with a true rock garden treasure. The moment of May flowering—when magenta stars blaze upon glossy, dark green cushions—makes all the effort worthwhile.
