Helianthemum is a genus of about 114 species of shrubs, subshrubs and some annuals or perennials, known as rock rose or frostweed, grown mainly for its bright five-petalled flowers in rockeries. The key to growing them is full sun and very well-drained soil.
Family
Cistaceae (Cist family)
Light
Full sun
Water
Water moderately while establishing, then let soil dry out between waterings; avoid waterlogging.
Soil
Free-draining, lean or sandy to gritty soil; tolerates poor soil.
Temperature
Hardy in many temperate climates; most tolerate cold in the ground, but protect potted plants from hard frost.
How easy
Easy
About
Helianthemum (), known as rock rose, sunrose, rushrose, or frostweed, is a genus of about 114 species of flowering plants in the family Cistaceae. They are widely distributed throughout the Northern Hemisphere, especially in the Mediterranean.
New World species formerly classified as Helianthemum have been transferred to genus Crocanthemum.
How to grow it
Several Helianthemum species, and the numerous hybrids and cultivars derived from them, are widely grown as ornamental plants, popular in rockeries. A broader range of colours is available among the cultivars, including bright salmon-pink to dark red. They are best grown in well-draining soil in full sun, and have a long flowering period from spring to summer. Numerous cultivars have gained the Royal Horticultural Society's Award of Garden Merit:
Where it grows
Helianthemum are known to form symbioses with mycorrhizal fungi. In the Mediterranean they are associated with Terfeziaceae, the desert truffles. Together, plant and fungus may have a beneficial effect on the arid local landscapes, preventing soil erosion and desertification. Some symbiotic pairs include Helianthemum salicifolium and the truffle Tirmania nivea, and H. guttatum and T. pinoyi.
Text excerpted from the Wikipedia article Helianthemum by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.