Pretty Butterflies and Burning Greens

A clump of stinging nettle plants. These are edible when cooked. They are also larval host plants for
A clump of stinging nettle plants. These are edible when cooked. They are also larval host plants for several species of butterflies.

 

Stinging nettle: a pernicious weed or something else altogether? I suppose it depends on where the nettles are growing. These particular plants are growing below my bean and cucumber trellis and there are a lot of them. Shortly after they emerged in April I dug several of the larger clumps and transplanted them to where an old horse manure heap used to be. The heap was tilled up, mixed with the soil underneath, and raked smooth. The soil is now rich and fluffy and they should do great there. The rest were moved to other locations and there’s a reason for that beyond getting a weed out of the garden.

Stinging nettle (Urtica dioica, Family Urticaceae) is a dioecious (rarely monoecious), rhizomatous perennial herbaceous plant growing to about one meter high. The leaves are in opposite pairs along the rough branched or unbranched stem, are elliptic in shape with toothed to serrate edges. The flowers are in clusters in the upper parts of the stem. Staminate (male) flowers have four tepals and four stamens. There is also a cup-shaped vestigial pistil (pistillode). Pistillate (female) flowers have four tepals and a tufted stigma. The innermost tepal encloses the fruit which is an achene. Occasionally, plants are monoecious.

Stinging nettle is named so because on it’s stems and leaves are hundreds of hairs that break open when touched piercing the skin and releasing irritating formic acid, histamine, and acetylcholine. The itching produced is short-lived for most people but for a few it can be quite painful and serious.

An edible plant when cooked, stinging nettle has been used as food by humans for centuries. Cooking nettle is simple and the new tender leaves can be steamed or simmered in water until wilted. The flavor is mild. Nettle leaves are high in protein (~4 gm per 100 gm cooked), calcium, iron, and vitamin A as beta-carotene. Older leaves are too tough to eat but can be dried and brewed into a bland tasting tea making it useful for stretching out other tea ingredients. Drying the leaves, like cooking, removes the stinging chemicals.

The stems of mature stinging nettle plants have long fibers that can be retted and twisted into cordage and string. The fibers can also be woven into cloth. Excavations of a Bronze Age burial site in Denmark show that cloth made from stinging nettle was being made and traded as far back as 2,800 years ago.

Propagation of stinging nettle is by seeds or by rhizome cuttings planted in rich soil. Once established it will live for many years. Because stinging nettle is a perennial plant it is an ideal plant for permaculture farming. It requires a rich, moist, loose soil high in organic matter. This can be easily achieved with the application of manure and rotting leaves and straw. A site with several hours of sunlight a day is best. Occasional disturbance to the patch such as light tilling helps to reinvigorate the planting.

Growing nettles is good for certain species of butterflies, too. Among the species whose caterpillars feed on nettles are the Red Admiral (Vanessa atalanta), Painted Lady (V. cardui), West Coast Lady (V. annabella), Satyr Anglewing (Polygonia satyrus), Comma (P. comma), Question Mark (P. interrogationis), Milbert’s Tortoiseshell (Nymphalis milberti), and Small Tortoiseshell (Aglais urticae).

Birds use stinging nettles, too. I have noticed flycatchers and goldfinches taking fibers from old dry stems to use for nesting material.

Although stinging nettle may not be an ideal plant for the garden it does have a place near the garden or maybe in a garden of it’s own. Planting stinging nettle will provide food for a wide variety of butterfly larva and the new shoots in the spring will provide food for you.

References

Bergfjord, C.; Mannering, U.; Frei, K. M.; Gleba, M.; Scharff, A. B.; Skals, I.; Heinemeier, J.; Nosch, M.-L.; and Holst, B. (2012). Nettle as a Distinct Bronze Age Textile Plant. Scientific Reports 2 Article Number: 664. doi:10.1038/srep00664

Butterflies and Moths of North America website

Cambridge University Botanic Garden website.

Flora of North America Vol. 3, Magnoliophyta: Magnoliidae and Hamamelidae. Urticaceae website.

Opler, P. A. and Malikul, V. (1992). Peterson Field Guides, Eastern Butterflies. Houghton Miflin Co., New York.

Rutto, L. K.; Xu, Y.; Ramirez, E.; and Brandt, M. (2013). Mineral Properties and Dietary Value of Raw and Processed Stinging Nettle (Urtica dioica L.). International Journal of Food Science. Volume 2013 (2013), Article ID 857120, 9 pages. http://dx.doi.org/10.1155/2013/857120

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