Plant of the Week: Salix humilis: Prairie Willow, Dwarf Willow
The University of Arkansas System Division of Agriculture does not promote, support or recommend plants featured in "Plant of the Week." Please consult your local Extension office for plants suitable for your region.
Each week since 1997, Dr. Gerald Klingaman has offered readers a unique window as he chronicles of the social history of plants.
"What always interested me was the background of the plants and how they got there and the people involved in bringing them forward," he said.
Klingaman, a retired extension horticulturist who is now operations director for the Botanical Garden of the Ozarks in Fayetteville, Arkansas, has created is a library of hundreds of plant histories that run in newspapers across the state and have become a favorite of gardeners in Arkansas and beyond. We hope you'll enjoy our extensive archive of his works and return each week to see what's new.
I’ve always liked willows. Perhaps it is their willfulness. As a plant, they just won’t be put down and often grow in spite of the circumstance they find themselves in. Mostly we think of willows as big, wispy trees, but they come in smaller sizes too. The Prairie or Dwarf Willow (Salix humilis) is a native willow that is scattered throughout Arkansas.
There are between 450 and 500 species of willows scattered throughout the Northern Hemisphere where they grow in usually moist, sunny locations. They belong to the willow family which first made its evolutionary debut about 55 million years ago in what is now North America which has over 100 species. Willows spread to Europe and later Asia, which is now the stronghold for the genus with over 250 species recognized there.
Prairie willow is found scattered in open areas across the eastern states where it forms a low growing deciduous shrub four to eight feet tall and wide. Willows never produce a true terminal bud, so side branches are always attempting to outgrow their neighbors, resulting in the wispy look of the group.
Prairie willow has linear, willow shaped leaves to four inches long that differ from other willows in that they essentially lack marginal teeth. The upper leaf surface is usually bright green and free of hairs while the lower leaf surface is often gray-pubescent. Fall color is brownish yellow.
Willows are dioecious with individual plants being either male or female. The yellow catkins shown in the accompanying photo are from a male plant taken in mid-April. At first the flowers break bud and form elongated, inch long whitish or silvery catkins that resemble pussy willow. As the flowers mature, they elongate and turn either yellow or brownish-gold in color. The female plants are similar but form a seed capsule filled with white, wind-borne seeds.
Willows have a long history of being useful to mankind. Early implements and all manner of basketry were often made from willows. The medicinal properties of willow have been recognized for over 5000 years, but my go-to source, the 1597 Gerard’s Herbal gives no mention to pain suppression properties of willows.
Native Americans relied on willow bark for temporary pain relief and fever suppression. In 1763 the medicinal properties of willow were spelled out in a paper published in England. In 1828 a French pharmacist crystalized the active ingredient and called it salicin. In 1897, a German named Felix Hoffman, created an artificial version of salicin derived from Spiraea plants. The new drug, officially called acetylsalicytic acid, was marketed by his employer Bayer as Aspirin, a word coined from “a” (without) plus “spirea”.
Prairie willow is available from native plant nurseries but will not be found in your local big box store. It is an interesting plant, but not an outstanding ornamental. It would make a nice, low maintenance shrub in out of the way places around the edges of the property or where a planting is needed to control erosion. It grows in drier sites than most willows and will tolerate moderate shade. Its leaves are eaten by several species of caterpillars that morph into attractive butterflies.
For more information about horticulture or to see other Plant of the Week columns, visit Extension’s Website, www.uaex.edu, or contact your county extension agent. The Cooperative Extension Service is part of the U of A Division of Agriculture.
Extension News - May 11, 2018