Phaca crotalariae Benth.
Astragalus limatus E.Sheld.
Astragalus preussii A.Gray
Tragacantha crotalariae (Benth.) Kuntze
Common Name: Salton Milkvetch
Astragalus crotalariae is a bushy perennial plant
The plant is used as an indicator of selenium deposits and is also a hyperaccumulator that can potentially remove selenium from polluted soils.
Astragalus crotalariae is a perennial herb for which at present there are no major known threats causing a population decline, but it is generally recorded as rare in its natural range. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[
Southwestern N. America - California, Arizona, northern Mexico (Baja Norte)
Sandy, gravelly areas in desert scrub, arid plains and washes, disturbed areas such as roadsides; at elevations from 60 - 250 metres[
|Conservation Status||Least Concern
|Other Uses Rating||
Astragalus crotalariae is native to arid and semi-arid regions of southwestern N. America where it is found at elevations below 250 metres. The summers are hot and the winters can bw very cold, with temperatures falling below freezing.
Requires a sunny position in a well-drained soil. Succeeds in poor soils.
Astragalus crotalariae is often found growing on selenium-rich soils and, when growing well, is believed to indicate the presence of selenium deposits. It has thus been used as an indicator plant of potential sites for mining selenium[
The plant also accumulates high levels of selenium in its foliage and has potential for use in removing selenium from contaminated soil by cutting and removing the foliage on a regular basis. The selenium is potentially recoverable from the foliage[
Seed - best sown as soon as it is ripe in a cold frame[
]. A period of cold stratification may help stored seed to germinate[
]. Stored seed, and perhaps also fresh seed, should be pre-soaked for 24 hours in hot water before sowing - but make sure that you do not cook the seed[
]. Any seed that does not swell should be carefully pricked with a needle, taking care not to damage the embryo, and re-soaked for a further 24 hours[
]. Germination can be slow and erratic but is usually within 4 - 9 weeks or more at 13°c if the seed is treated or sown fresh[
]. As soon as it is large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter, planting them out into their permanent positions in late spring or early summer, after the last expected frosts.