You might think of thistles as thorny weeds, but many varieties have lovely flowers and some, like the artichoke, are edible. The milk thistle produces seeds from it flowers that have medicinal properties. Many thistle species belong to the large plant family Asteraceae, which includes not only asters but also sunflowers and other cultivated flowers.
The invasive Scotch thistle has a rich history and folklore. In 1470, King James III ordered that the image of this plant's flower be imprinted on silver coins. In 1540, King James V established the Order of the Thistle. He and his 12 knights wore a badge depicting a star, a thistle and the words "no one harms me without punishment." The globe artichoke is believed to be native to the Mediterranean and Canary Islands. The word "artichoke" comes from the Italian word articiocco and a Ligurian term, articoclos, meaning pinecone. Artichokes were eaten in ancient Greek and Rome, where they were also thought to have aphrodisiac properties. In the 16th century, Catherine de Medici helped to spread the popularity of artichokes in France. It was not until 1806 that the artichoke arrived in the United States, thanks to the French who immigrated to Louisiana. However, cultivated artichokes no longer exist in that part of the country, but they became a major agricultural crop in California, where the Spanish introduced them in the late 1800s.
Milk thistle, Silybum marianum, is often used in medicinal preparations for conditions of the gallbladder and liver, including hepatitis and cirrhosis. After this plant flowers, it forms seeds, which are the source of medicines. Clinical trials have found only a few minor side effects, such as diarrhoea and upset stomachs. Some people report allergic reactions connected with milk thistle use. Always discuss alternative medical treatments with your physician, especially if you have a serious disease such as hepatitis or cirrhosis.
The delicious globe artichoke is the flower bud of a thistle known as Cynara scolymus. If not harvested, the bud develops into a feathery, pink-lavender blossom that blooms in summer and is popular in dried flower arrangements. Globe artichokes constitute a large agricultural crop in central coastal California, with Castroville claiming the title of "Artichoke Center of the World." If it is left to flower and form seeds, even this desirable thistle can become invasive. If you grow the globe artichoke in your home garden, you can let one or two of the flowers go to seed and then collect them to plant for more artichoke plants. This species requires an average amount of water on a regular basis and if you grow it in rich soil with a high organic content, there's no need to add fertiliser.
The Echinops genus contains more than 100 species of globe thistles, some of which are prized for their showy, unusual flowers. The Veitch's Blue variety is an attractive thistle that is cultivated for its lovely lavender ball-shaped flowers, which bloom in summer. These unusual blossoms dry well and are often used in dried flower arrangements. Other varieties include Blue Glow and Arctic Glow. The genus Cirsium includes an ornamental thistle called Atropurpureum, which produces a large magenta-pink head. It's easy to grow in full sun with fertile, well-drained, slightly acidic soil, similar conditions for most of the thistles.
Star Thistle and Other Invasives
Yellow star thistle, or Centaurea solstitialis, is classified as a noxious weed in California, where it covers more than 1,000,000 acres. In the mid-1800s, alfalfa that contained star thistle seed was introduced from South America, and this weed began its invasion of the continental United States. However, it is native to Asia Minor, the Middle East and south Central Europe. Artichoke thistle or cardoon, Canadian thistle and many other species of this plant are classified as invasive. Scotch thistle runs rampant in Washington and other Western states. It is Scotland's national emblem and has globe-shaped dark pink or lavender flower heads that grow as large as two inches in diameter. Scotch thistle exists as a weed on ranch land in the Western United States and chokes out grazing land for livestock. The invasive thistles can spread quickly. For example, Scotch thistle first appeared in Utah in 1963. By the early 1990s, it covered 56,000 acres in 22 counties.