Ground Nut
Apios americana

Family: Fabaceae or Leguminosae

What it is like

Apios americana is a PERENNIAL growing to 1.2 m (4ft). See above for USDA hardiness. It is hardy to UK zone 3. It is in leaf from April to November, in flower from June to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. 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 and can grow in very acid soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 1.2

Where it is found

Usually found in low damp bottomland or riparian woods and thickets, it is also often found round ancient Indian campsites.

N. America - Pennsylvania. Occasionally naturalized in S. Europe.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 5

Tuber - raw or cooked. A delicious flavour somewhat like roasted sweet potatoes, it always receives very high marks in taste trials with us. The tuber can also be dried and ground into a powder then used as a thickening in soups etc or can be added to cereal flours when making bread. Tubers contain 17% crude protein, this is more than 3 times that found in potatoes. The tubers can be harvested in their first year but they take 2 - 3 years to become a sizeable crop. They can be harvested at any time of the year but are at their best in the autumn. The tubers can also be harvested in the autumn and will store until at least the spring. Yields of 2.3 kilos of tubers per plant have been achieved. Seed - cooked. Rather small and not produced very freely, they are used like peas and beans. A good source of protein, they can be ground into a powder and added to cereals when making bread etc. Young seedpods.

Root: includes bulbs, corms, tubers, rhizomes etc.

Seed: includes nuts, cereals, peas and beans.

Seedpod: things such as Okra, French and Runner beans.

Medicine

Rating: 1

The tubers were used in folk remedies for that cancerous condition known as "Proud Flesh" in New England. Nuts were boiled and made into a plaster, "For to eat out the proud flesh they (the Indians) take a kind of earth nut boyled and stamped".

Other

Rating: 3

There is one report that the plant contains a latex which could be used in the production of rubber.

Companion: Companion planting is the careful placement of plants (especially vegetables and herbs) which have been shown to have beneficial effects on one another.

Latex: A source of rubber.

Agroforestry Services: Nitrogen: Plants that contribute to nitrogen fixation include the legume family – Fabaceae.

Edible Beans: Grown for Edible Beans.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

New Crop for Tubers: Most new crops were important wild plants until recently, although some are the result of hybridization. They have been developed in the last few, decades. What they have in common is that they are currently cultivated by farmers.

Staple Crop: Protein: (16+ percent protein, 0-15 percent oil). Annuals include beans, chickpeas, lentils, cowpeas, and pigeon peas. Perennials include perennial beans, nuts, leaf protein concentrates, and edible milks.

Agroforestry Services: Nitrogen: Plants that contribute to nitrogen fixation include the legume family – Fabaceae.

Edible Beans: Grown for Edible Beans.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

New Crop for Tubers: Most new crops were important wild plants until recently, although some are the result of hybridization. They have been developed in the last few, decades. What they have in common is that they are currently cultivated by farmers.

Staple Crop: Protein: (16+ percent protein, 0-15 percent oil). Annuals include beans, chickpeas, lentils, cowpeas, and pigeon peas. Perennials include perennial beans, nuts, leaf protein concentrates, and edible milks.

Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.

Food Forest: Plants for Edible Forest Gardens and Food Forests.

Nitrogen Fixer: Plants that fix nitrogen in the soil

Scented Plants: Plants noted for their scent

How it is grown

Prefers a light rich soil and a sunny position. When grown in a warm dry situation in a well-drained sandy soil, the plants will be long lived with the tuberous roots increasing in size and number each year. Another report says that the plant prefers light dappled shade. It tolerates acid soils. Dislikes windy situations. Groundnut is reported to tolerate an annual precipitation in the range of 97 to 117cm, an average annual temperature range of 9.9 to 20.3°C and a pH in the range of 4.5 to 7.0. It tolerates a range of climatic conditions and produces well in cool temperate zones as well as the subtropical conditions of South Florida. Whilst most reports suggest that this species should be cold hardy in all parts of Britain, one report says that the plants may require protection in severe winters. The groundnut has occasionally been cultivated for its edible root and has the potential to become a commercial crop. Cultivars have been selected in the past for higher yields and larger tubers, it is said that the yields from some of these cultivars can rival potato crops. Some of these cultivars are gradually becoming available in Britain. The best yields are obtained when the plant is left in the ground for at least two growing seasons. Yields of 30 tonnes per hectare have been achieved from weed crops growing in a field of cranberries. This species has been grown in the past in S. Europe and has been suggested as a nitrogen-fixing edible ornamental for permaculturalists. The plant forms long thin roots which enlarge at intervals along their length to form the tubers, the effect is somewhat like a necklace. Plants can be invasive once they are established and have become a weed of cultivated cranberry crops in N. America. A climbing plant, twining around the thin branches of other plants for support. The flowers have a scent of violets. 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. For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. Herbaceous. A suckering vine sending up suckers some distance main plant. The root pattern is tuberous with swollen potato-like roots .

Propagating it: Seed - pre-soak for 3 hours in tepid water and sow February/March in a cold frame. The seed usually germinates in 1 - 3 months at 15°c. When large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in the greenhouse for their first winter, planting them out in late spring or early summer. Division can be carried out at almost any time of the year, though spring is probably the best time. Simply dig up the roots, harvest the tubers and replant them where you want the plants to grow. It is also possible to harvest the tuber in winter, store them in a cool fairly dry but frost-free place over the winter and then plant them out in the spring. The tubers lose moisture rapidly once they have been harvested, so make sure that you store them in a damp medium such as leafmold.

Best place to grow: Woodland Garden Sunny Edge; Cultivated Beds;

Habit: Perennial

Hardiness: 3-7

Growth:

Soil: Light (sandy), medium

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Its other names

Local names

Synonyms

A. tuberosa. Glycine tuberosa.