The flowering of the Marsh Marigold (Caltha palustris) is another sign of spring! These bright yellow flowers are a part of the buttercup family and bloom in our neighborhood around the end of April or beginning of May.
As you can tell by the name, the Marsh Marigold likes to grow in wet areas. Their preferred habits are marshes, ditches, and wet woodlands. Besides the yellow flowers they have glossy heart shaped leaves and thick, hollow stems. These perennial plants grow in clumps and can range from 1 -2 feet tall.
Marsh Marigolds leaves are somewhat edible. They are often referred to as potherbs. What this means is that they are only edible after you treat them with boiled water. Collards and kale are also considered potherbs. But as we will find out, collards and kale are more freindly to the digestive system.
The Lady Bird Johnson Flower Center says, “Cooked, early spring greens are edible. Cover the young leaves with 2-3 changes of boiling water until barely tender; cut into bite-sized pieces, salt lightly, and cover with butter and some vinegar. Tightly closed buds can be pickled after covering with boiling water as described for leaves.” This page goes on to say that the plant juices can cause blistering and inflammation on the skin and mucus membranes. The plant may also cause gastric upset if ingested.
The US Forest Service states, “handling the plant can cause skin irritation, and uncooked parts are toxic to human consumption. This is due to irritant yellow oil called protoanemonin. Cattle and horses are also poisoned by consuming marsh marigold.”
It turns out that the irritant protoanemonin is toxin found in all plants in the buttercup family. When the plant is cut or broken, a chemical reaction happens where the glucoside inside transform into glucose and protoanemonin. I found the most information about protoanemonin on veterinarian websites, so buttercups must produce this toxin to protect themselves from grazing animals.
Based on all this information, Marsh Marigolds will not be making it on to my dinner menu anytime soon! I’ll stick with my collards, kale, and beet greens.
Resources:
Naturalist Weekly 
While boiling isn’t an elaborate way to make a plant edible, I always wonder about how early people figured out what parts and when certain plants should be harvested. It’s a long process just to test berries raw form for example. You eat one and wait to see if you get any stomach upset, then the next day you eat maybe three more and wait another 24-48hours to see if you get any digestive upset. If after the first or second test you get violently ill you point it out to others and say “Don’t eat this,” or classify it as yet another one of nature’s enemas.
Hi Melanie, Such a great point! I am also in awe about how people figured out these things. I guess you could watch other animals and see what they do? But I guess I don’t know of many animals that boil there food.
Beautiful photos and interesting information.
Thanks Susan!