Astragalus pycnocladus
At a glance
- Lifecycle
- Perennial (hardy)
- Exposure
- Full sun
Cultivation
We have very little information on this species and do not know if it will be hardy in Britain, though judging by its native range it could succeed outdoors in many parts of this country. Whilst it is likely to tolerate low temperatures it may not be so happy with a wet winter. The following notes are based on the general needs of the genus. Requires a dry well-drained soil in a sunny position. Plants are intolerant of root disturbance and are best planted in their final positions whilst still small. This plant is a sub-shrub and although it produces woody stems these tend to die back almost to the base each winter. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby.
Propagation
Seed - best sown as soon as it is ripe in a cold frame. 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.
Edible uses
A source of gum tragacanth - used as a thickener in confections.
Material uses
Gum tragacanth is obtained from the stem (see above). It has a wide range of uses including:- a thickening agent in preparing dyes for calico printing, textile dyes and for dressing fabrics, it is also a thickener in making glues, water colours, ink (where it supplies a gloss), it is a binding agent in paper making, a culture medium in laboratories etc.
Habitat
Not known
Native range
W. Asia.