Ferns

General & History

While Ferns have been with us forever and are common in many areas, they have played only a very minor role as food for humans or livestock. This is particularly due to toxicity, the fern's first line of defense against being eaten. The varieties identified as "edible" are still toxic, but in the small amounts we are likely to eat them they don't pose significant risk to most individuals.

While many ferns are prized as decoratives, some are major pests, particularly the Old World Climbing Fern (Lygodium microphyllum) which is currently strangling large areas of the Everglades in Florida, and the aquatic fern Giant Salvinia (Salvinia molesta) which is covering entire lakes in Hawaii and elsewhere. We cannot be too bitter about aquatic ferns though, since they may have been instrumental in reversing a previous global warming episode - by covering all the lakes formed by melting ice caps and absorbing carbon dioxide. They could come in handy again for that. Also, extracts of Salvinia molesta may be effective against cancers - currently under study.

Varieties

Bracken Fern

A common fern in temperate climates, immature Bracken fronds are eaten as a vegetable in many parts of the world and particularly in Korea, Japan and parts of China. Native Americans dug up, cooked and ate the rhizomes from which the fronds sprout. These are still used in Japan, Sichuan, China and elsewhere as a starch source (see noodles, below).   Details and Cooking.

Bracken Fern is toxic to livestock when a significant part of their diet. For humans fresh fern should be cooked (simmered 10 minutes) and eaten in moderation. One of the toxins is a thiamine inhibitor that can cause a vitamin deficiency if consumed for an extended period. Bracken also contains a substance identified as a carcinogen and has been placed in the same risk category as Coffee and Sassafras by the American Cancer Society. Study is ongoing but still inconclusive, but demographics do not indicate a notable danger.

We found these noodles, made from starch extracted from bracken fern root, in one of the large Asian markets here in Los Angeles. The strands were 0.063 inch diameter and 20 inches long, folded in the middle. Cooked, they resemble large, dark colored bean starch noodles, but have a lightly earthy flavor, while bean starch noodles are pretty neutral. These come from Sichuan China, ingredients: fern root starch, rapeseed oil.

Ostrich Fern

This fern, common in the northern U.S and Canada and northern and eastern Europe provides the "fiddleheads" sold in commerce. They have a flavor somewhat similar to asparagus and are a little crunchy if not over cooked. They are popular in season (Spring) where the ferns grow, but are just a curiosity here in Southern California, at more than U.S. 2006 $10 per pound from yuppie outlets like Whole Foods Markets.

Ostrich Fern is considered safe, or about as safe as ferns get. Some people have shown sensitivity to unidentified toxins in them, but most reported incidents of toxicity are from mistaking some other fern for Ostrich Fern. Simmering Ostrich fiddleheads for 10 minutes is said to make them safe for people sensitive to them. Ostrich Ferns are reported to be free of the carcinogens and thiamine inhibitors of the Bracken Fern.

Buying, Storing & Cooking   Fiddleheads should be 1 to 1-1/2 inches diameter with no more than 2 inches of stem projecting from them. They should be crisp, not limp. Refrigerated they will keep up to 10 days but lose flavor rapidly. Rub off the brown chaff and trim the end of the stem before cooking.

Royal Fern

This is one of the largest ferns in Europe, with a range extending through East Asia to Korea and Japan. There is a closely related North American species, O. spectabilis. While the photo specimens were packed in China, the only place you are likely to find them in North America is in Korean markets, as they are a popular vegetable in Korea. They are generally vacuum packed in water after being boiled and may be labeled "Boiled Royal Fern" or "Osmund". The largest stem in the photo are about 3/8 inch diameter, but most are 1/4 inch or less.

Vegetable Fern

This fern is found throughout Asia and Oceana. Young fronds are commonly eaten throughout its range. They are often stir fried or use in salads. They may have very small amounts of fern toxins but are regarded as safe. Photo by Judgefloro distributed under license Creative Commons Attribution-ShareAlike 4.0 International

Field Horsetail

This Horsetail can be found in the arctic and temperate zones of the northen hemisphere. This is the only species of Horsetail that is edible. The edible part is the tan fertile stem that arives in spring, before the inedible green sterile fronds come forth for the rest of the growing year.

The fertile stem has rings of dry leaves around it, but they are easy to scrape off. The conical spore head is bitter and discarded. The stems are par boiled for about 10 minutes, then simmered in a soup-like sauce of soy sauce, sake, sugar and dashi for a few minutes, then covered and left to cool in the sauce. It is generally eaten as a garnish over rice. Photo by Krzysztof Ziarnek, Kenraiz distributed under license Creative Commons Attribution-ShareAlike 4.0 International

Sword Fern

This fern, originating from north-eastern Australia and the Himilayan foothills, is now found in tropical regions worldwide, often as an unwelcome invasive. It is a semi-evergreen "grow anywhere" fern, often clinging to the bark of trees, crevaces in rocks, or in the ground. It isn't a good house plant because it wants more sunlight.

The edible stolens (tubers) are the ferns water storage units. They are most often eaten raw, tasting similar to Jerusalem Artichokes and with similar crunch. They can also be roasted. Photo by Anastasiya Lvova distributed under license Creative Commons Attribution-ShareAlike 4.0 International. Photo by Alex Abair distributed under license Creative Commons Attribution-ShareAlike 4.0 International.

Licorice Fern

This Fern is native to a coastal strip along the Pacific Northwest of North America, from southern Alaska to northern California. There is an isolated population in Idaho. It lives in very moist shady places, and is often found growing on moss covered Bigleaf Maple. The fronds grow singly from a long rhizome. Pieces of this "root" have long been chewed on by native tribes for its sweetness and flavor. Today it is appreciated by foragers and is used in braises by some cooks in the region. The fronds are not edible. Photo by Kfediuk distributed under license Creative Commons Attribution-ShareAlike 4.0 International.

Other Ferns