Astragalus crassicarpus

Astragalus crassicarpus, known as ground plum or buffalo plum, is a perennial species of flowering plant in the legume family, Fabaceae, native to North America. It was described in 1813. The fruit is edible and was used by Native Americans as food and horse medicine. It is a host of afranius duskywing larvae. It is also known as groundplum milkvetch and pomme de prairie.

Description

A perennial growing to 0.5 m tall at a moderate rate, hardy to UK zone 7. Hermaphroditic flowers are pollinated by bees and butterflies; the plant is self-fertile and fixes nitrogen. Notable for attracting wildlife. Grows in light sandy to medium loamy, well-drained soils across mildly acidic to mildly alkaline pH levels. Requires full sun and prefers dry soil.

Edible Uses

Edible Parts: Seedpod Edible Uses: The thick fleshy unripe seedpods, which resemble green plums, are eaten raw or cooked. They are highly esteemed. The pods are about 25mm in diameter.

Traditional Uses

The unripe fruit or pods are edible raw or cooked. The pods can be cooked as spices for pickles.

This uses section is brief — help expand it

Medicinal Uses

Antispasmodic Haemostatic Stimulant A compound decoction or infusion of the root has been used to treat fits and convulsions and has been used on bleeding wounds. It has also been taken or used externally as a stimulant.

Known Hazards

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.

Where It Grows

Seed pod, Fruit,

Cultivation

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. The stems are sometimes prostrate. This species is somewhat polymorphic and is separated into a number of distinct species by some botanists. The form sometimes known as A. mexicanus has larger seedpods than the type, up to 35mm in diameter. 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. The leaves and young shoots can be harvested in spring and early summer. The seeds are typically harvested in late summer to early autumn. Milk Vetch usually flowers from late spring to mid-summer.

Propagation

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.

Other Uses

Nitrogen Fixer. Milk Vetch is often used as a cover crop and for erosion control. It improves soil fertility through nitrogen fixation and can be used in mixed plantings to enhance biodiversity. Provides shelter for beneficial invertebrates: insects and other arthropods. A general nectary plant [1-2]. 1. Nectary - Flowers rich in nectar and pollen: Yes – Milk Vetch species produce flowers that are rich in nectar, making them attractive to pollinators such as bees and butterflies. 2. Wildlife - Food (Fruit, Seeds, Leaf litter, Shelter, Nesting, Roosting): Yes – The seeds of Milk Vetch are edible and can serve as food for various wildlife. The plant’s foliage may also provide cover for small animals, although it is not typically used for nesting. 3. Invertebrate Shelter (Overwintering sites, Leaf litter, Groundcover): Yes – Milk Vetch can provide a habitat for invertebrates, and its leaves contribute to leaf litter that supports beneficial insects. Some species may spread out enough to offer ground cover. 4. Pest Confuser (Smell): No – Milk Vetch is not specifically recognized for its ability to confuse pests through its scent. Special Uses Food Forest Nitrogen Fixer

Other Information

Fabaceae

Notes

A herb. It grows 50 cm tall. It is a bean plant that keeps growing from year to year. The stems lie along the ground and it forms mats. It has branches near the base. The leaves are compound with 17-25 leaflets. They are oblong. They are smooth above and hairy underneath. The flowers are yellowish-white with a purple tinged keel. They are 2 cm long. Several flowers occur in loose clusters. The fruit are reddish fleshy pods. They are round and 2 cm across.

Synonyms

Also Known As

Ground plum, Buffalo bean, Groundplum milk-vetch, Buffalo pea.

References (16)

• Beckstrom-Sternberg, Stephen M., and James A. Duke. "The Foodplant Database." http://probe.nalusda.gov:8300/cgi-bin/browse/foodplantdb.(ACEDB version 4.0 - data version July 1994) (As Astragalus caryocarpus)
• Bircher, A. G. & Bircher, W. H., 2000, Encyclopedia of Fruit Trees and Edible Flowering Plants in Egypt and the Subtropics. AUC Press. p 46
• Bot. Reg. 2: t. 176. 1816
• Cormack, R. G. H., 1967, Wild Flowers of Alberta. Commercial Printers Edmonton, Canada. p 170
• Crawford, M., 2012, How to grow Perennial Vegetables. Green Books. p 117

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