There are many plants in our landscape that we don’t want, at least in that location and we call them weeds. A major one in soybean and other crops is one from that same bean family. It’s called sicklepod (Senna obtusifolia).
Sicklepod is an annual that has paired yellow flowers, curved pods up to six inches long and foliage that looks like peanut leaves. Individual plant specimens can sometimes get more than six feet tall but are usually shorter. When mature, pods burst open releasing the seeds. They are dark brown, flattened, irregularly shaped and less than a quarter inch long.
Plants grow well in the coastal plain. Sicklepod is adapted to sandy soils with adequate drainage and fertility. They’re common on cropland and roadsides and they spread quickly. They spread primarily by seed, so cutting them prior to flowering can be effective. Keeping them from becoming established in the first place is best.
Beyond agricultural fields, sicklepod can also invade our vegetable and flower gardens. Someone brought me a sample of this a while ago and asked for its identification. He said it was a really pretty plant with bright yellow flowers, interesting foliage and showy pods. He wanted to know if he should save the seed and if I wanted some. I chuckled and politely declined.
It’s not the first time someone has noticed a plant they found attractive and wanted it for ornamental use. That’s one reason kudzu became established here. Though flowers are pretty, and foliage often forms an enticing contrast to ornamental plants, this one is best eliminated from your landscape.
Some people call it coffeeweed, because seeds from relatives of it were once roasted and used as a substitute for coffee. However, another common name is arsenic weed. That should throw up a red flag. Years ago, plants were used medicinally but they seldom are today.
Although young shoots can be eaten as cooked greens, they are bitter unless cooking water is changed a couple times. Other plant parts particularly seeds contain toxins called anthraquinones. My recommendation to foragers and herbalists is to remove this plant and destroy it whenever you see it growing.
Most livestock refuse to eat hay contaminated with sicklepod. They won’t graze live specimens either, so eliminating it from these areas is important. Wildlife don’t find it palatable and move to other things. Heavy infestations also lower crop yields. Furthermore, seeds are sometimes difficult to separate from soybeans, drastically lowering their market value.
Many broadleaf herbicides will kill sicklepod, so they are less of a problem in a crop like corn or wheat than they are in cotton or soybeans. Since they are in the same family as soybeans, many chemicals that will control sicklepod will harm soybeans. Roundup ready varieties have alleviated competition from sicklepod, but it’s still a nuisance.
Another reason to control sicklepod is that it harbors insects and diseases common to crop plants. Eliminating sicklepod can help lessen problems these other organisms cause. Sometimes pretty flowers and showy foliage are not sufficient reasons to let these invaders populate your landscape.
Ted Manzer teaches agriculture at Northeastern High School (firstname.lastname@example.org).