PlantFiles: Groundnut, Potato Bean
Apios americana

A delicate-looking twiner with attractive flowers and tasty tubers, Apios Americana prefers sunny, moist locations and really thrives if given something to get it off the ground. The vines never seem to grow more that 6' in my area, and will grow along the ground with reduced vigor if it has nothing to climb.

The plant does spread, but it is easily controlled as the roots are shallow. Planting in a raised bed or using plastic edging works well. Unrestrained, I can see this plant becoming a problem as the tubers store plenty of energy to continue sprouting if you only pull the stem.

Similar to asparagus or Chinese yams this perennial tuber crop produces best when left alone for the first year (or two). Harvesting in the first year after planting will likely be a disappointment. The tubers grow horizontally in a linear chain along the main root and are easily lifted with a garden fork as they are fairly close to the surface. Young tubers are round and smooth and usually golf ball sized or smaller, older tubers can get fist sized and lumpy. All are good to eat.

As pointed out in other posts, there are both diploid (seed producing) and triploid (flowers but doesn't fruit) variants, with most (but not all) Northern varieties being triploid and reproducing only vegetatively.

Tuber size and number, and leaflet number (5, or 7) are variable, as is the number of flowers per plant.

The tubers of this plant are delicious and grow prolifically in my garden. The tubers are analyzed to have a protein content of about three times that of potato. The flowers are beautiful as well. I have built an 8 foot high trellis and have had these plants growing for three years now. This species is native from Florida north all the way into Canada. The type I have are fertile diploids that yield viable seed from which I have successfully germinated new plants.

It is reported that infertile triploid types tend to dominate in the northern end of the natural range and propagation is by dispersal of the tubers only. This species was once an important food source for Native Americans and paleoagronomists believe that humans carried tubers with them in migrations to replant thus extending the range of this plant.

This plant is a nightmare in my garden, the bane of my existence, growing unchecked for years before my arrival. The pods have imbedded themselves deep in the root crowns of Siberian Iris and Daylilies, grow up everywhere and weigh the foliage down into an unsightly mess. I've cleared out beds and dug down- it re-roots from tne whisper of a shred of root...Roundup kills it eventually but I've been working on one bed I cleared nearly a year ago and it's still coming up. I won't re-plant until I'm sure it's gone. No flower is worth it!

I really like this plant. I have it growing again the brick wall of my house, bordered by the concrete pathway to the door so it's well contained. The soil isn't great quality there and it doesn't go very deep but the plant does well, rewarding me with lots of flowers. This is only the second year so I can't comment on the edible qualities.

It gets part sun and winds around a lilac shrub. I plan on removing the lilac and training the groundnut to grow up the wall with some kind of a trellis.

This plant can be very invasive. I have to tear it out by the bushel to keep it from smothering my shrubs. I rated it as a neutral because it's decorative, easy to grow and not particular about soil. The tubers are edible, but small.

Groundnut, Potato Bean Apios americana is native to Texas and other States.

This plant is beautiful but aggressive. I wanted it to cover a fence and it is covering a large clump of pampas grass. It dies back to the ground in winter and comes back faithfully.

Until a year ago I had no clue what this vine was. It was always there. I love it. It is delicate and very abundant. Thanks to your comments I now know how to move them and give them away. They are literally coming up in my lawn and I hate just weeding them and killing them. They are very invasive, but they such a nice touch to my garden that I do not like killing them.

Physical Characteristics: Perennial growing to 1.2 meters. It is hardy to zone 3. It is in leaf from April to November, in flower from June to September. The scented flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects. It can fix Nitrogen.

The plant prefers light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very acid soil. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.

Habitats and Possible Locations: Woodland, Cultivated Beds, Sunny Edges.

Edible Uses: Root; Seed; Seedpod.

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.

Root (Fresh weight): In grammes per 100gm weight of food: Protein: 17

Medicinal Uses: Disclaimer:
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: Latex. There is one report that the plant contains a latex which could be used in the production of rubber.

Cultivation details: 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.

While 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 tons per acre 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.

Propagation: Seed - pre-soak for 3 hours in tepid water and sow February/March in a cold frame. The seed usually germinates in 1 to 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.

Scent: Flowers: Fresh: The flowers have a scent of violets.