These small edible tubers come from a perennial plant in the mint (Lamiaceae) family, that has long been cultivated in China and Japan (where they are normally served pickled). The cultivation of crosnes has spread to France as an ingredient in cuisine japonaise, but otherwise, they are not a well-known food crop globally.
They have a flavour similar to that of a sunchoke, but slightly nuttier. Difficult to clean en masse, they are more likely to be used as a garnish than a main course.
The tubers also bear a striking resemblance to maggots! So if those seem unappetizing, the mint-like foliage is also edible, but isn’t especially delectable: most sources class it as a famine food.
They are hardy in USDA zones 4-8, and like many members of this family, tolerate water-logged soil.
Apparently, if a nearby market can be found for them, they sell for roughly $80 CAD (60€) /kg, with a yield being roughly 1 kg/m2. All but a single tuber can be harvested from each plant every year. They are also an abundant source of stachyose, which is a partially indigestible sugar that possibly promotes a healthy gut, pulmonary, and reproductive microbiota.
“None of the top five plants eaten by people — wheat, corn, rice, potatoes and soybeans — can tolerate salt,” agricultural experts Edward P. Glenn, J. Jed Brown and James W. O’Leary wrote 16 years ago, in a definitive Scientific American article. “Expose them to seawater, and they droop, shrivel and die within days.”
Now that scientific principle has been cracked — by a Dutch potato that drinks in salt and doesn’t break a sweat. A researcher and a farmer in the Netherlands teamed up to experiment with crops that could thrive in seawater. They set up shop on the island of Texel, a land rich with salt marshes. Along the way, they met an elderly Dutch farmer with an encyclopedic knowledge of thousands of potato varieties. Together, they created the salt-tolerant potato.
If you’re thinking this means a future of pre-salted veggies, hold it right there.
“What we find is that, if you tease a plant with salt, it compensates with more sugar,” says Dr. Argen de Vos, the researching half of the duo. “You’d have to eat many many kilos of potatoes before you’d exceed your recommended salt intake.”