medicinal plant

Sowthistle – a new weed in my yard

sowthistle1A new weed has sprouted in my yard. With the help of a botanist at the Arizona-Sonora Desert Museum, this new plant is identified as the genus Sonchus, commonly called sowthistle. Sowthistle species occur in temperate zones worldwide. Arizona has two species, Common Sowthistle (Sonchus oleraceus), the one in my yard, and Spiny Sowthistle (Sonchus asper). These plants are related to dandelions and are members of the sunflower family. For an idea of the plant size, the large leaf in the center of the photo is 10 inches long.

The name “Sowthistle” refers to the fact that pigs are especially fond of the leaves and stems. So are rabbits. This plant is also called “hare thistle” or “hare lettuce” in some parts of the world.

The leaves are also used by humans, especially in Chinese cooking. The leaves can be eaten as a salad green or cooked and used like spinach. Blanching removes a slightly bitter taste. (Source) I have not tried it.

“This plant has powerful medicinal properties, with some toxicity, but at the same time it is also highly nutritious. It contains, per 100g, around 30mg of vitamin C, 1500 mg of calcium and 45 mg of iIron. The dried leaves contain up to 28g of protein per 100g – a great nutritional supplement. Use only young leaves as edibles, raw, in salads or cooked, as spinach.” (Source)

Medicinal uses are the same as for dandelions:

“In the past, dandelion roots and leaves were used to treat liver problems. Native Americans also boiled dandelion in water and took it to treat kidney disease, swelling, skin problems, heartburn, and upset stomach. In traditional Chinese medicine (TCM), dandelion has been used to treat stomach problems, appendicitis, and breast problems, such as inflammation or lack of milk flow. In Europe, dandelion was used in remedies for fever, boils, eye problems, diabetes, and diarrhea.” (See more from the University of Maryland Medical Center.)

Sow thistles exude a milky latex when any part of the plant is cut or damaged, and it is from this fact that the plants obtained the common name, “sow thistle”, as they were fed to lactating sows in the belief that milk production would increase. Sow thistles are known as “milk thistles” in some regions, although true milk thistles belong to the genus Silybum. (Source)

The yellow flowers are about 1.25 inches in diameter and attract bees, flies, and aphids. The flowers turn into dandelion-like tufts and the seeds go floating off in the wind.

Common Sowthistle is classified as an annual herb and can grow up to four feet high. Other species of Sonchus are perennials.

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Desert Tobacco, a pretty but poisonous desert plant

The winter rains have caused many perennial plants to bloom this spring. Among those blooming in my yard is Desert Tobacco (Nicotiana trigonophylla, aka Nicotiana obtusifolia). This bush-like plant gets up to three feet high and blossoms with trumpet-shaped greenish-white to pale yellow flowers. The large leaves are oblong, green, and clasp the stem. The seed capsules contain many small brown seeds. The entire plant is sticky and covered with small hairs.

Desert-tobacco5Desert tobacco can be found throughout the Southwest at elevations below 5,000 feet. It favors disturbed ground and desert washes.

This plant is in the Solanaceae (Nightshade) family, a family which contains some very poisonous plants such as Deadly Nightshade and Sacred Datura. The family also includes potatoes, tomatoes, and chili peppers.

As the scientific name implies, the plant contains nicotine and other alkaloids such as anabasine. These alkaloids can be poisonous in sufficient dosage. The USDA estimates the LD50 dose (lethal to 50% in rats) is 11 mg/kg for anabasine and 50 mg/kg for nicotine. According to An Illustrated Guide to Arizona Weeds, from The University of Arizona Press, the leaves and young stems are the most poisonous parts. Desert Tobacco is poisonous to all kinds of livestock and to humans; cattle and horses are poisoned more often than sheep under normal range conditions. The minimum lethal dose of desert tobacco is about 2 percent of the animal’s weight on a green weight basis.

In spite of the possibly poisonous nature, or maybe because of its qualities, the plant has been used for pleasure, ceremonies, and medicine by native people. According to the National Park Service, leaves were chewed, smoked, or used in a drinkable decoction as part of rituals in many groups, such as to control rain, increase crop production, divining and improve health of community, to drive away malevolent powers. It was smoked by travelers to clear away all danger and ensure blessing from spiritual guides. A poultice was applied to cuts, bruises, swellings and other wounds. An infusion was used as an emetic. Leaf smoke blown into the ear and covered with a warm pad treated earaches.

I’ve seen this plant promoted by nurseries as a landscaping option.

Desert-tobacco3

As the seed pods develop, you may see the plants covered with small dark bugs in the family Thyreocoridae. They feed on the developing seeds.