Wikipedia: Erodium is a genus of flowering plants in the botanical family Geraniaceae. The genus includes about 60 species, native to North Africa, Indomalaya, The Middle East, and Australia. They are perennials, annuals, or subshrubs, with five-petalled flowers in shades of white, pink, and purple, that strongly resemble the better-known Geranium (cranesbill). American species are known as filarees or heron's bill, whereas Eurasian ones are usually called storksbills in English.
Erodiums are the Cinderellas of the geranium family: beautiful, worthy, and neglected, although usually easy to propagate and cultivate. Erodium reichardii(syn. E. chamaedryoides) is widely available from retail nurseries in the West for use as a ground cover; small collections of a few species or hybrids of unusual erodiums are sometimes found in collectors’ rock gardens. However, there are many excellent plants that are generally unavailable, neglected, or ignored. Although their cold hardiness can be a problem in the central and eastern parts of the United States, erodiums will grow successfully in most of the West Coast states. Many erodium grow naturally in calcareous soils, and respond well to the addition of dolomite, oyster grit, or even concrete chips to potting soils that are neutral to somewhat acidic. As with many other genera, only a few members of the genus Erodium have silver leaves.
Robin Parer/Pacific Horticulture