Published by Brian Wagner on 11/6/25 in “Growing Flowers from Seed.”
Arabis blepharophylla (commonly known as coast rock cress) is a rare wildflower endemic to California, especially known for its low-growing rosettes and showy magenta/purple flowers. It is adapted to serpentile soils (i.e., soils derived from ultramafic rocks, especially serpentinite – and which is very difficult for most plants given the high amounts of calcium and heavy metals). If you have serpentile soil, look no further.
The species has been used in hybrid propagation of various ‘Rock Cress’ plants sold in garden centres – and if you’ve ever purchased a rock cress plant as such, chances are one of its parents was A. blepharophylla. This species, however, is mostly found in the San Francisco Bay Area – and it grows on sun-exposed slopes, on coastal scrub, rocky chaparral margins and coastal foothill forest margins. It will put up with a bit of shade but will be happiest with 4-6 hours of sunlight during the day.
Like most plants native to scrubland ecosystems, it wants/needs lots of drainage and poor soil. When you think of ‘scrubland’ you should think of the wasteland deserts outside of Los Angeles where the mafia take their victims to die. So-called scrubland ecosystems are very low in water, but they have enough water for certain kinds of plants. Like Rock Cress (and small woody shrubs).
Growing from Seed
Seeds have a non-deep physiological dormancy and are fairly easy to germinate. If seeds are freshly harvested, consider cold stratifying them for 6 weeks at 4C (40F) and then incubate with light around 21C (70F). Seeds should germinate in 7-10 days. Dried seeds will typically germinate faster, and they have a shelf life of at least 3 years.