About
Helianthemum nummularium, the common rock rose, is a low, spreading evergreen shrub to 15 cm tall with tiny, oval, grey-green leaves. Saucer-shaped, sulphur-yellow flowers to 2.5 cm across are produced over a long period from late spring to summer. A classic and indispensable rock garden plant for a sunny, very well-drained position.
About the genus
Helianthemum, the rock roses, are bushy or spreading evergreen shrubs with small, paired leaves and saucer-shaped, five-petalled flowers in white, yellow, pink, red or orange borne in short racemes in spring and early summer. Excellent plants for sunny, well-drained rock gardens and wall tops.
Growing conditions
SunlightFull sun
Soil typeChalk, Clay, Loam, Sand
Soil pHAcid, Alkaline, Neutral
Soil moistureMoist but well-drained, Well-drained
AspectSouth-facing, East-facing, West-facing
ExposureExposed, Sheltered
UK hardinessH5
Plant details
Plant typeAlpine Rockery, Shrubs
HabitMatforming
FoliageEvergreen
Height0.1-0.5 metres
Spread0.1-0.5 metres
Time to full height5-10 years
Suggested usesGravel garden, Rock garden, Wildlife gardens
Native toEurope, SW Asia
Care notes
CultivationPrefers alkaline to neutral, moist but well-drained soil in full sun, but will tolerate acid soil and dry conditions. Survives well amongst short grass. This plant was included in the RHS Helianthemum (rock rose) trial 2024-2026
PruningPruning group 10 after flowering
PropagationPropagate by seed sown in autumn, or take softwood cuttings in late spring or early summer
Pest resistanceGenerally pest-free
Disease resistanceMay be susceptible to honey fungus in gardens where it is present but insufficient data to determine degree of susceptibility