About

Petrophytum caespitosum, mat rock spiraea, is a low-growing, mat-forming, evergreen subshrub from western North America producing dense mats of spatula-shaped, silver-grey leaves and slender, upright spikes of tiny, creamy-white flowers in summer. A rewarding alpine for a sunny, very well-drained rock garden or scree.

About the genus

Petrophytum are low-growing, mat-forming, evergreen subshrubs from western North America with small, grey-green leaves and slender spikes of tiny, creamy-white flowers in summer. Grown in sunny, very well-drained rock gardens and screes.

Plant details

Suggested usesBorders, containers, mixed plantings.

Care notes

CultivationPlant in well-drained soil. Water during establishment.
PruningRemove dead growth as needed.
PropagationPropagate by division, cuttings, or seed.
Pest resistanceGenerally pest-free.
Disease resistanceGenerally disease-resistant.