Astragalus strobiliferus
Family: Fabaceae or Leguminosae
What it is like
Astragalus strobiliferus is a deciduous Shrub growing to 0.1 m (0ft 3in). The species is hermaphrodite (has both male and female organs) and is pollinated by Bees, Lepidoptera (Moths & Butterflies). It can fix Nitrogen. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry soil.
Height (m): 0.1
Where it is found
Not known
E. Asia - Western Himalayas at heights up to 4,000 metres from Kashmir to Kunawar.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 2
A source of gum tragacanth - used as a thickener in confections. Some exudes naturally from the plant, more can be obtained by incision of the stem about 5cm below ground level.
Gum: can be chewed as a chewing gum or can often be used as a sweetener or thickening agent in foods.
Medicine
Rating: 0
Other
Rating: 2
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.
Gum: Gums have a wide range of uses, especially as stabilizers, emulsifiers, thickening agents, adhesives etc.
Nitrogen Fixer: Plants that fix nitrogen in the soil
How it is grown
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. Succeeds in poor soils. 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. Many members of this genus can be difficult to grow, this may be due partly to a lack of their specific bacterial associations in the soil.
Propagating it: 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.
Best place to grow: Cultivated Beds;
Habit: Shrub
Hardiness:
Growth:
Soil: Light (sandy), medium
Shade: No shade
Moisture: Dry
Things to keep in mind
Many members of this genus contain toxic glycosides. All species with edible seedpods can be distinguished by their fleshy round or oval seedpod that looks somewhat like a greengage. A number of species can also accumulate toxic levels of selenium when grown in soils that are relatively rich in that element.