Common Name: Ground Nut

General Information

Apios americana is a herbaceous perennial, climbing plant, sending out thin, branching stems up to 6 metres long from underground tubers. The stems scramble over the ground, twining into the surrounding vegetation for support.
The groundnut is commonly harvested from the wild for local use as a food. It has occasionally been cultivated for its edible root and has excellent potential to become a commercial crop[, ].
Plants can be invasive once they are established[] and have become a weed of cultivated cranberry crops in N. America[].

Known Hazards

None known

Botanical References

,

Range

N. America - Ontario to New Brunswick, south to Texas and Florida

Habitat

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

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.20 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Apios americana is a plant of the temperate zone, where it is found at elevations up to 1,000 metres. It grows best in areas where annual daytime temperatures are within the range 10 - 20°c, but can tolerate 8 - 30°c[]. When dormant, the plant can survive temperatures down to about -40°c, though young growth can be damaged by frosts[]. It prefers a mean annual rainfall in the range 1,000 - 1,200mm, but tolerates 700 - 1,500mm[]. It tolerates a range of climatic conditions, producing well in cool temperate zones as well as the subtropical conditions of South Florida[].
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[]. Prefers a pH in the range 5 - 7.5, tolerating 4.5 - 8.5[]. Dislikes windy situations[].
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[].
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[].

Edible Uses

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[]. The seedpods are 5 - 13cm long, containing 6 - 13 small seeds[].

Young seedpods[, , , ]. The seedpods are up to 13cm long[].

Medicinal

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 Uses

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

Propagation

Seed - pre-soak for 3 hours in tepid water and sow late winter/early spring 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.