Ouch! I’m not kidding – thistles are edible. You can eat the leaves, stems, roots and flowers. And guess what? The extremely invasive Canada thistle is reportedly the tastiest. Now, I’m not suggesting you go out and grow a bunch of Canada thistle to eat. In fact that would be illegal since Canada thistle is considered a noxious weed in 43 states including Wisconsin, and is on the “Restricted” list of the Wisconsin DNR’s new rule NR 40, meaning it cannot be transported, transferred or introduced.
The thrill of breaking the law aside, why in the world would you want to eat Canada or any other type of thistle? Well, they are reportedly very tasty. And they are good for you: they contain calcium and potassium and many vitamins and other minerals. Thistles help support liver and gallbladder functions, lower cholesterol, prevent constipation, help to ward off cancer and act as a diuretic.
So, how do you go about eating a thistle? Let’s start with the stems, the best part. Prime time to harvest stems is when the flower buds are forming but not yet open. Look for stems that are about the thickness of a pencil. WEAR GLOVES, and holding the flower buds at the top of the plant in one hand, take a knife or scissors in the other hand and cut the leaves away from the smooth stem. After the leaves are removed, cut the stem, peel it and cut it crosswise into pieces an inch or so long. Stems can be used in stir fries, steamed, baked, boiled or eaten raw. The flavor is similar to celery or artichokes depending on the species of thistle and growing conditions.
Leaves are good too. WEAR GLOVES and remove the spines by cutting around the edges with a scissors. This is easily done, even with a child’s blunt-end scissors. Turn each leaf over and make sure you have removed all the spines before eating! The leaves are tender and mild tasting. Wash them and use them fresh as a salad green or steam them in salted water.
Leaves can also be frozen for future use. Blanch the washed and trimmed leaves by quickly dipping them in boiling water, then ice water. Shake the water off, pack in plastic zipper bags and freeze.
Thistle roots can be dug or pulled up easily after a good rain (WEAR GLOVES). Most species have a single taproot, like a carrot. Roots are best when the leaves are still in a basal rosette, but definitely dig them before the tall flower stalk is formed. They become tough and fibrous as the plant matures. The roots can be washed and scraped, and eaten raw, boiled or roasted. Roots can also be boiled for several hours until soft and mushy and then dried and ground into flour.
Artichokes area really the flower bracts of a cultivated thistle species. Just like artichokes, some thistle flowers have edible hearts. The heart is at the bottom of the flower, where it meets the stem. Cook the entire flowerhead, then remove the flower and you are left with the heart. Some thistles have larger edible hearts than others – you’ll have to experiment. You might not think they would be worth the trouble until you find out how good they taste. The flower hearts are packed with nutrition just like the rest of the plant.
The flowers of Canada thistle make a delicious chewing gum and the flower head of bull thistle can be used to curdle milk. (Why would you want to curdle milk you ask? You’d want to do that if you were making cheese.) To do this, mash the flowers until a liquid is released. A very small amount of this liquid will curdle a large amount of milk.
Top to bottom, thistles are delicious and nutritious, but WEAR GLOVES!
CAUTION: Do not eat thistles from roadsides or those growing in or adjacent to an area that may have been sprayed with a pesticide.
Cream of Thistle Soup
1 pound trimmed thistle leaves and chopped stems
2 cups water
4 teaspoons chicken bouillon granules
1/2 cup chopped onion
1/4 teaspoon garlic powder
1/4 cup butter
1/4 cup all-purpose flour
3 cups half-and-half
salt and pepper to taste
1. Place thistles, water, bouillon, onion, and garlic powder in a large pot over medium-high heat. Bring to a boil, then reduce heat to medium-low and simmer until thistles are tender. Meanwhile, melt the butter in a small saucepan and whisk in the flour until smooth. Cook for 2 minutes. Slowly stir in half-and-half; mix until smooth. Pour the half-and-half into the thistles and simmer until thickened, about 10 minutes. Season to taste with salt and pepper.