Watercress (Nasturtium officinale), is a tasty aquatic leaf vegetable with a rich history in Madison County, Alabama. In the first half of the 20th century, the economic landscape of Madison County was dominated by cotton and textile mills, but ponds of watercress grown for export to major cities dotted the landscape. Today, the watercress business in Alabama is nearly extinct, but the plant still thrives in the wild even though it is not native to the Americas. You can find in in cold, fresh running springs. Right now the spring weather has it aggressively growing, so it’s the perfect time to harvest.
Before talking about the virtues of watercress, it’s important to cover some safety information up front about liver flukes and a disease called Fasciola. Many livestock species carry a flatworm parasite (Fasciola hepatica and Fasciola gigantica) which can infect people, and this parasite is in their manure. Runoff from pastures combined with the presence of freshwater snails who can act as a host means that you should never, ever eat wild water plants raw. While Fasciola infections are both rare in the United States and treatable, it’s simply not worth the risk. Like many foods, watercress must be properly prepared to be consumed safely. There are two ways to neutralize the risk of eating wild aquatic plants.
- Completely submerge washed watercress in a 6% vinegar solution for 5-10 minutes. Important note: the household vinegar sold in grocery aisles is 5% — it’s not strong enough. You can purchase and use 10% horticultural vinegar. Or, you can use potassium permanganate to soak the plants for the same amount of time.
- Cook the watercress thoroughly.
Watercress is worth the effort, both nutritionally and for its taste. It’s very high in vitamin K and a particularly good source of vitamin A, vitamin C, calcium, potassium and manganese. It has a sweet flavor, but with a peppery bite and the hint of bitterness that you’d expect from any member of the mustard family. Just how peppery and bitter will depend on the batch you get, but wild watercress is generally stronger tasting than the cultivated versions found in food markets.
It is excellent used as a fresh green on sandwiches, in a mixed green salad, or in vegetable soup. The rich flavor stands up well to oily, fatty and creamy soups, but can also stand alone as the primary flavor in a starchy soup, like one made from potatoes. If you are a fan of mustard and turnip greens, you may enjoy preparing watercress the same way as a side dish.
My greens are sitting in a bucket of water on the back porch, still growing. This batch is destined to be a non-traditional ingredient in a matzo ball soup to flavor the broth and give it a little kick.