Friday, April 22, 2011

Is This a Weed?

Horsetail and henbit and shot weed, oh my! Nettles that sting, geraniums gone wild, and "dandy" lions - these are a few of the plants referred to as "weeds" in the Northwest. Can you identify them in your yard? Here's a quick tutorial.

This is horsetail (Equisetum hymale), one of the oldest plants on earth. If you have ever tried to get rid of it, you understand how it has survived since prehistoric times. This is one tough plant. Chemicals won't kill it. Pulling it out like a regular weed stimulates the plant to send up even more new shoots. The most effective way to get rid of it is to starve it out by cutting stems to the ground so leaves cannot photosynthesize. Covering the area with layers of newspaper topped with bark and leaving it alone for several months may finish the job.

This is red deadnettle (Lamium purpureum), a cousin of henbit. This plant is not invasive and can easily be pulled out if it is not to your liking. You'll note that it has square stems as do all members of the mint family. The stem tips and flowers are edible but not particularly flavorful. This is the only weed I know of that has its own Facebook page.

Shotweed (Cardimine hirstuta) is hard to photograph because its stems and flowers are so delicate they all but disappear. You can easily recognize the tight rosette of leaves at the base, however, and once those little white flowers fade, you can't miss the explosive burst of seed that comes your way when you touch the plant. The seed explosion is, of course, how it gets its name, shot weed. It also explains how it manages to be so invasive - seed goes everywhere. It is edible as a bitter herb.

Stinging nettles (Urtica dioecia) can certainly get your attention. Tiny hairs on the stems and leaves act like hypodermic needles, injecting histamine, acetylcholine and serotonin, among other chemicals, into the skin which produces a profound stinging sensation. In spite of that, this plant has a long history of medicinal uses including pain relief, easing arthritis symptoms, hay fever and skin problems. Stinging nettles are edible - the chemicals responsible for the sting go away when the plant is immersed in water and/or cooked. The flavor is said to be similar to spinach and it is used in soups, polenta and even cheese making.
Wild geranium (Geranium robertianum) is also known as Robert's herb or "stinky Bob" because of the strong odor emitted when you pull it up or brush against it. In late spring, this lacy plant blooms with small, star-shaped, 5-petaled pink flowers. It is shallow rooted and probably the easiest plant to pull out of the ground there is. It isn't a particular problem in urban gardens, but in the forest it will quickly overtake native ground cover.

Of course, everyone knows this one, the dandelion (Taraxicum official). Much loved by children for their sunny, yellow flowers and big, puffy, seed heads, these plants present a problem for gardeners who let their populations get out of control. However, a soil knife  or dandelion weeder will easily pop them out. All you need is time and patience. If you have a particularly large crop, you might consider exploring this plant's various culinary and medicinal properties. Dandelion greens have long been used as a spring tonic. And the flowers are used to make wine.