Pyrenean Rockbeauty

Petrocallis pyrenaica is a delightful and diminutive crucifer found on the highest limestone screes of the Alps and Pyrenees. In the UK garden, it forms a soft, moss-like cushion of finely divided, bright green leaves that rarely exceeds 2-3cm in height. In late spring, the entire cushion is virtually obliterated by a dense covering of tiny, four-petalled, fragrant flowers that range from pale lilac to soft pink. It is a slow-growing species that demands the best possible drainage and a position in full sun to keep its habit tight and characteristic. It is an ideal plant for a trough, a tufa rock, or a crevice in a raised bed where its delicate beauty can be observed closely. While hardy to H5, it is sensitive to winter humidity; a Victorian-style glass 'cloche' or a position in an alpine house can help preserve the cushion in particularly wet regions of the UK. It is a charming choice for those seeking to replicate high-altitude flora.

Sun: Full sun.

Soil: Very well-drained, gritty, alkaline soil.

Hardiness: H5 — down to −15°C.

Flowering: May, Jun.