Identify this Pea

I’d like to know if anyone can help identify what sort of plant we have.  This is a pea (or bean if you prefer) that has been reseeding itself continuously since we moved here.  It only occurs in one weedy corner of the front pasture near the winter yard we use for the pigs.  Because this area is bounded by a fence, a loading chute, a driveway, and a hay storage area, the plants are currently isolated to a 20 x 20 patch.

Pea on Sidewalk

The whole plant, about 40 inches tall.  Picked this weekend.

The most unique aspect of this plant is the stalk.  All along its length it has a double-bladed structure that I think can be called a Phylloclade, but I could be wrong.   This is a fascinating adaptation to allow photosynthesis along the entire length of the stem.  It may explain why the cattle like eating this down to the dirt when given the chance.  Its stalk grows in a segmented fashion, with segments changing direction every four inches or so.

Pea Stalk Close Up

Both the main stalk and the leaf stems are bladed.  This gives a lot of photosynthetic capacity to a plant that doesn’t have a large amount of leaf area compared to other peas and beans.

Other physical aspects:  It grows about three or four feet tall, but it depends on adjacent stalks for support using tendrils.  It can successfully compete with aggressive stands of thistles, burdock, grape vines, and goldenrod.  It flowers continuously from late June until frost, with each new segment taking a shot at flowering and producing peas.  The pea pods fall off as they ripen, which probably helps reseeding if the conditions at one part of the season aren’t ideal. The seeds taste somewhere between garden peas and edamame.  Mature seeds are a bit smaller than most garden peas, and usually look a bit deflated.   The pods aren’t palatable (pigs and cows eat them, but they are just roughage).  The plant will quickly regrow after being grazed or driven over, but I’m not sure how many regrazes or tramplings it can handle.

Pea Stems

Early July with the pods just forming.

It seems to be some sort of winter pea.  I’ve looked through seed catalogs, but all the examples of winter peas I’ve been able to find have normal round pea stalks with a lot more tendrils.

Because of the taste, there is also the remote possibility the plant is some crazy outcross or throwback from hybrid soybeans.  The pods aren’t fuzzy like most soy I’ve seen, and none of the other characteristics seem similar.  I can’t really see this being a soybean, but I’ll leave that as a marginal possibility.

I’ve discussed before the challenges I’ve had with getting annual forages to grow with wet, heavy soils and late planting dates.  A pea like this one that could presumably be broadcast, perhaps frost seeded or graze-tramped, into an existing stand of perennial grasses without any tillage or expensive no-till equipment.  Obviously there would be a big challenge in seed saving at a large enough scale to make this practical, especially with a plant that drops its pods continuously making mechanical harvesting impractical. And from the plant breeding perspective, there are a lot of more productive options that could yield more tons of forage per acre.  But as a grazier the idea of a home-grown, locally-adapted, self-propagating annual legume is appealing.

7 Comments on “Identify this Pea

  1. When I’ve needed to identify something and been unable to find it using google images, I’ve turned to our University of Wisconsin Extension specialists and they have been helpful.

  2. Ed, on further investigation I found better sweet pea photos that show (at least on some varieties) blades on the stems. Other photos don’t show blades, but perhaps some varieties don’t have them, or those without are misidentified? In any case, thanks for your help. So sweet pea is the new pasture prodigy…

  3. My take is it’s a pea. I think it is Sweet Pea. Looks just like it.

    • It could be in the larger vetch family. We have vetch aplenty here, but this would be unique from everything else I’ve seen since it only has two leaves at each branching. Most vetches have a large number of opposite leaves. I read of one Asian vetch with two leaves but it is smaller and has none of the ribbing on the stems. Also the seed pods being 3-4 inches long seem excessive compared to the vetches I’ve seen. Not saying you are wrong, just noting that it doesn’t fit neatly into my mental taxonomy of vetch.

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