Fields, Forests & Wetlands Foods of Eastern North America
A Complete Wild Food Guide
Season: Spring & Summer
Urban, Rural or Both: Both, more common in Rural settings
Earthnut Pea (Lathyrus tuberosus). It has a few common names: Earthnut, Earthnut Pea, Aardaker, Tuberous Sweetpea & Tuber Vetchling. Be careful with common names, they can refer to many plants. It is a member of the pea family.
It is a vine, and considered a noxious weed in Ontario - commercial corn and soy farmers hate this one. They tend to show up in fields and along fences. They have nice pink and white flowers in the summer. At one time they were a crop food in other parts of the world. The problem with them as a crop is they can be hit or miss. Sometimes a good crop, often, very little.
You just follow a vine to the ground and dig up the soil around it. There will be tubers at the end of roots that are the edible part. They are ready to dig up in the fall after the flowers are gone.This vine has a great feature that makes identifying it fairly straight forward. The leaf and the tendril are one unit. The leaflets are on the tendrils, there is only one pair of opposite leaflets (two leaves in total) that are Ovate (Oval) shaped, and some of the leaflets have shallow, rounded indentations on the tip - the opposite of a pointed tip. At the base of the leaf/tendril where it meets the vine, there is a pair of very small leaves that sometimes look like a pair of wings. At the other end, the tendril/leaf stem divides into two separate tendrils. The only plant that looks a little like it is the Lathyrus hirsutus. It has two leaflets as well. The difference is the leaflets on the Lathyrus hirsutus are long and thin with a pointed tip, while with the one you want, the leaflets are oval shaped, and do not come to a sharp pointed tip. As a way of remembering: with the Earth nut, the each leaflet's outline shape is about the same as the tuber's outline shape.
Make sure you cook them. I have read in places you can eat them raw, but there are also reports that raw they can be slightly toxic, so don't take the chance - cook them. Steam, boil or bake. They don't take very long to cook. Baked until tender, they are very good and worth the effort if you find a few of them in soil that is easy to dig in like sandy soil.
Growing this plant in your home garden:
This could be grown at home if you have loamy, alkaline to neutral soil with full sun. I don't recommend it however. It is a serious weed where it likes to grow, so if you have the right conditions, you shouldn't have to grow it - you should just be able to find it. Also, it is a hit and miss crop, which means, after you go through the trouble of getting it established, you might get very little in the way of Earthnuts.
- Plant Size: 1.2 meters or (4 feet) climbing or trailing vine. (Uses tendrils to climb with)
- Duration: Perennial
- Leaf Shape: Two opposite Ovate leaflets, often with the tips indented slightly (like a shallow lobe at the very tip of the leaf). The leaflets are on the tendril itself. There is a pair of wing-like leaves right at the base of the leaf/tendril stem at the vine. If there are more than two leaflets on the tendril, you may have a Lathyrus, but not a (Lathyrus tuberosus).
- Leaf Opposite or Alternate on vine: Alternate
- Leaf Size: 2-4.5 cm (3/4 to 1 3/4 inches) long
- Leaf Margin: Entire (smooth edged)
- Leaf Notes: Sometimes the leaves come to a blunt point, sometimes rounded, sometimes an indentation. The leaf is often slightly folded along the middle vein so that the upper side is concave.
- Flowers: Purple-red or pink. Sometimes mauve, sometimes with white near the edges of petals. Looks like a typical Sweetpea flower - that is sort of Snapdragon flower like. The flower is vertically bilaterally symmetrical, which means: if you imagine a line from top to bottom of the center of the flower, each side is a mirror image. If you divide it horizontally, the halves are not mirror images. Strongly scented.
- Fruit: pod, that looks like a Pea pod. 2.8-4.0 cm long. Not completely cylindrical, but not flat either.
- Habitat: Likes friable (soft, loamy), aerated soils - in other words, not hard compacted soils. Likes open areas with full sun. Fields, waste areas, sides of roads, meadows. Often grows around small trees and shrubs and climbs them. Along fence lines, ploughed fields. Neutral to alkaline soils - does not grow in acidic soils. All in all - likes the same conditions as corn and soy.
- Recipe search on the web here (Google search) and here (Bing search).
- Pictures on the web here (Google images) and here (Bing images).
- USDA distribution map and plant profile here.
- The Biota of North America Program (BONAP) distribution map here. BONAP map color key here.
Earthnut Pea (Lathyrus tuberosus) drawing. Illustration by: Christiaan Sepp. From: Flora Batava. Volume 3 (1814) by Jan Kops.
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