Phaseolus acutifolius
Origin: Unknown (Southwest US/Northern Mexico)
Improvement status: Cultivar
Seeds per packet: ~20
Germination tested 12/2023: 98%
Life cycle: Annual
EFN INTRODUCTION. We love tepary beans. This underutilized species of bean is the result of a separate domestication event from common bean, lima bean, and all other bean species. It was domesticated from tiny wild beans that still live in what's now northern Mexico and the US southwest, home to many Indigenous peoples whose ancestors first began consuming Phaseolus acutifolius directly from the wild, before eventually bringing it into cultivation and improving it year after year through selection. This particular tepary bean came to us from the USDA's National Plant Germplasm System, but unfortunately the trail goes cold there. Unlike most other tepary beans in the collection, the origin of this one is unknown — but it most certainly traces its roots to one or more Indigenous people in that region. We are hopeful that its uniquely beautiful pattern — intensely mottled black and white in nearly equal measures — will help get it identified one of these days. In the meantime, we are happy to be offering it here under the temporary name "Black & White."
Though well-adapted to the desert southwest, this tepary bean thrived in 2023 during our grow-out in collaboration with The Seed Farm at Princeton University. With very little attention, and only a small bamboo trellis, a few plants produced a pound of dry seeds. The few "shelly" beans we harvested to cook and eat were delicious. The seeds also remained in excellent condition even though the pods were all beginning to turn black and moldy (Princeton is far more rainy and humid than the desert). Nate harvested these seeds on a rainy day too, and hardly any seeds at all were moldy or discolored or anything like that. Even in a year when common beans grown nearby were sprouting in their pods due to the weather, these tepary beans held up just fine. The seeds were grown with no irrigation, which is typical of tepary beans — in fact, some tepary beans are noted for their ability to grow to maturity with just one rainfall or watering after planting!
Unlike nearly all other edible beans, tepary beans can flower and set seed even when night-time temperatures are high — a very important trait as the planet warms. Teparies are also very weed resistant. We often leave them to their own devices to grow up with the weeds: the bean plants simply use the weeds as trellises and we then harvest the seedpods out of the mess as they all die and dry down. Like most legumes, teparies also fix nitrogen and thus make great companion plants for crops like corn, sorghum, sunflowers, okra, and more, allowing you to produce two crops from a space where you otherwise might only grow one. Tepary beans can climb on the other plants without damaging them due to the relatively small nature of tepary beans leaves, vines, and pods, compared to common and other beans. Young pods can be eaten, as can the unripe fresh seeds (which are substantially larger than the dried seeds). They work well as a dry bean for soups or stews — and one of Chef Sean Sherman's signature dishes at Owamni by the Sioux Chef is a delicious tepary bean dip!
GROWING TIPS: Direct seed after all danger of frost has passed. Space plants about a foot apart. Provide a trellis up to 3 or 4 feet tall, or grow in the presence of tall sturdy plants.
