Native wildlife is adapted to and dependent on specific plants. One reason that invasive species can become invasive, taking over large areas and displacing native species, is because they are largely unused by local wildlife. Recent research revealed the shocking discrepancy that on average, in the US Mid-Atlantic region, native plants support 15 times as many native caterpillar species as non-native plants (Shepherd, 2022). If a plant’s relative value to an ecosystem was ranked according to the number of other species that benefit from it, hog peanut would certainly receive a high score.
The hog peanut is a legume, a member of the pea, bean and clover family. The seeds, which are types of beans, were a minor but common food of several Native American tribes, particularly the Plains tribes. The seeds also provide food for multiple species of birds and rodents and of course, wild hogs, the source of the plant’s common name. The seeds may feed squirrels when nuts are scarce. The caterpillars of some skipper butterflies eat the leaves, as do several leaf beetles. Like other legume family members, the hog peanut fixes soil nitrogen, making an nutrient essential for plant growth available to other nearby plants. The hog peanut benefits birds, mammals, insects and other plants, providing an unusually diverse range of ecosystem benevolence. Native species like Amphicarpaea bracteata are the ecological glue that holds ecosystems together.
Hog peanut is part of the traditional cornfield polyculture of the Sierra Norte de Puebla, Mexico. Seeds are sown with the corn and then harvested and toasted on a skillet when the fields are plowed at the end of the season (Rhizowen, 2009).
Further north, woods mice will gather the largest seeds of the hog peanut and store them in underground chambers in the fall and early winter. Such storage chambers may contain a pint or more of seeds (Martin, 1938). Persons of the Dakota nation had high regard for the plant and very high regard for the woods mouse, which they called the Bean Mouse, and while historically they did take bean caches they found during winters of food scarcity, they always left payment of some kind, such as some corn, suet, or other food, in exchange for the beans they took (Martin, 1938).
There is a Dakota legend which involves the hog peanut and woods mice (Martin, 1938). A certain woman plundered the storehouse of some Hintunka people (bean mice). She robbed them of their entire food supply without giving anything in return. The next night this woman heard a woman in the woods crying and saying, “O, what will my poor children do now?” It was the voice of the Hintunka woman crying over the hungry children. The same night the unjust woman who had done the wrong had a dream. In her dream, Hunka, the spirit of kinship of all life, appeared to her and said: “You should not have taken the food from the Hintunka people. Take back the food to them, or some other in its place, or else your own children shall cry from hunger.” Next morning, the woman told her husband of this vision, and he said, “You would better do as Hunka tells you to do.” But the woman was hard-hearted and perverse, and would not make restitution for the wrong she had done. A short time afterward a great prairie fire came, driven by a strong wind, and swept over the place where the unjust woman and her family were camping. The fire consumed her tipi and everything it contained, and the people barely escaped with their lives. They had no food nor shelter; they wandered destitute on the prairie, and the children cried from hunger.
The hog peanut is a nitrogen-fixing pea vine which requires some shade a rich soil. While it is trifoliate like poison ivy (three leaflets), unlike poison ivy, hog peanut climbs by twining, wrapping around and around whatever supporting is available. The thin, twining stems may be smooth or hairy.
Hog peanuts have visible blooms from mid-summer into the fall, clusters of tuberous flowers which may be white, pale pink, lilac or pale purple.
Stuff Almost Nobody Knows:
(for the perpetually curious)
People generally assume that flowering plants of a specific type will produce a single type of seed. Hog peanut produces two different types of flowers and seeds, both capable of growing the next generation of hog peanuts. The genus name Amphicarpaea refers to this capability (Greek amphi (of both kinds) and carpos (fruit) (University of Wisconsin Horticulture, 2022).
The hog peanut produces flowers on its upper branches that look like flowers typically associated with pea plants. These flowers then develop into flat, oblong spotted pods that are pointed at both ends, are generally cross-pollinated and usually contain three or four seeds which are eventually ballistically dispersed. There is nothing surprising about a member of the pea family growing seed pods from a flower cluster on its upper branches.
It is surprising that the lower branches of the hog peanut produce thin stalks that search for crevices in the soil and that these stalks have tiny self-pollinated flowers at their tips which rest on or under the ground. These tiny flowers then develop into large single-seeded modified seedpods buried just below the soil surface. These subterranean seeds can be up to ½ inch in diameter, much larger than the seeds that develop in the aerial seedpods.
One plant, two seeds. One highly visible seed type, explosively disseminated, and one hidden seed type planted beneath the ground surface. The larger hidden seeds are self-pollinated and therefore genetically identical to the parent plant. The smaller, more widely distributed aerial seeds are more genetically diverse. If conditions are ideal for the parent plant, conditions should logically be ideal for the hidden, self-planted seeds. If conditions are in flux, the relative durability and genetic diversity of the aerial seeds may make those seeds best positioned to support a flourishing next generation of hog peanut. Although amphicarpy isn’t fully understood, this plant appears to have taken steps to hedge its bets regarding how to adapt to a wide range of conditions by having a seed type suitable for times of stability and a seed type suitable for times of uncertainty.
Because it has a distribution largely confined to thickets and woodlands, some assume that partial shade is the preferred habitat of the species. An alternative explanation is that hog peanut is preferentially found in wooded areas because it can’t effectively compete with the plants in the open, given that when hog peanut is grown under cultivation in experimental plots, it thrives without shade (Martin, 1938). If the hog peanut is a species that is easily outcompeted, it is likely particularly vulnerable to the modern onslaught of invasive plant species as these plants are all aggressive competitors for habitat. The broad degree of ecosystem support provided by Amphicarpaea bracteata merits a reciprocal effort to make sure that a place in the ecosystem for this plant remains available. If we can figure out how to extend some of the generosity to this plant that this plant extends to its own neighbors, we can be confident that the hog peanut will figure out how to pass the favor forward.
Black Squirrel Farms strives for accuracy but everyone makes mistakes sometimes. We’re happy to update our information if needed. Please contact us if you spot an error or have a suggested edit, update or information inclusion. Help is welcome.
Black Squirrel Farms is not a provider of medical advice. We share information and ideas but do not make health recommendations for or against the use of any traditional medicinal plant for any reason.
Martin, John N., 1938. “Some Features in the Life History of Amphicarpa Bracteata (L.) Fernald (Hog Peanut)”, Proceedings of the Iowa Academy of Science, Vol. 45 , No. 1, Art. 11., https://scholarworks.uni.edu/cgi/viewcontent.cgi?article=4293&context=pias
Hurteau, Matthew, 2003. “AMERICAN HOGPEANUT, Amphicarpaea bracteata Fern.”. USDA NRCS National Plant Data Center Plant Guide. https://adminplants.sc.egov.usda.gov/plantguide/pdf/cs_ambr2.pdf
Rhizowen (online blogger), 2009. “Amphicarpaea – The Talented Mr Talet”. Radix: Root Crop Research and Ruminations. https://radix4roots.blogspot.com/2009/02/amphicarpaea-talented-mr-talet.html
Shepherd, Mark, 2022 “For Wildlife And Humans, Native Plants Are A Key To Climate Resilience.” https://xerces.org/blog/for-wildlife-and-humans-native-plants-are-key-to-climate-resilience
University of Wisconsin Horticulture, Division of Extension, 2022. “American Hog-peanut, Amphicarpaea bracteata”, https://hort.extension.wisc.edu/articles/american-hog-peanut-amphicarpaea-bracteata
http://www.illinoiswildflowers.info, 2022. “Hog Peanut, Amphicarpaea bracteata, Bean family (Fabaceae)”. https://www.illinoiswildflowers.info/savanna/plants/hog_peanut.html#:~:text=Various%20vertebrate%20animals%20also%20use,also%20feeds%20on%20the%20foliage.