Dalmatian Toadflax
Dalmation toadflax. Image courtesy staff CDFA, California Dept. of Food & Agriculture, Integrated Pest Control Branch
DB: This is Earth and Sky with a story about a beautiful plant – loved by gardeners a century ago – gone wild.
JB: Dalmatian toadflax is a plant with bright yellow, heart-shaped flowers – sometimes called “butter and eggs.” Its native soil is in the Black Sea region of Eurasia. In the 19th century, gardeners charmed by its beauty brought the plant to North America.
DB: Dalmatian toadflax appeared in the intermountain West in the 1890s. There it found dry conditions similar to those in Eurasia. Even better, from the point of view of the toadflax, the North American West lacked predators this plant had had to withstand back home.
JB: Dalmatian toadflax reproduces rapidly by putting out horizontal roots called runners. Uprooting toadflax is tough – a two-centimeter root fragment can quickly grow into a new plant. And each plant produces as many as 500,000 wind borne seeds. These reproductive strategies – combined with its good looks – make Dalmatian toadflax a destructive weed in the North American West. After it gains a toehold, toadflax crowds out native plants, stealing water and nutrients.
DB: From Arizona to Alberta, fields of toadflax have replaced many diverse native plant populations. Ecologists are working to stop its spread. Thanks today to the National Fish and Wildlife Foundation and to the U.S. Forest Service. We’re Byrd and Block for Earth and Sky.
The following individuals were interviewed for today’s show. Our thanks to:
Dr. George Beck
Professor
Bioagricultural Sciences & Pest Management
University of Colorado
Barry Meyers-Rice
Wildland Invasives Species Program
The Nature Conservancy
Edward Smith
Regional Ecologist
The Nature Conservancy of Arizona
More resources:
The Nature Conservancy – Wildland Invasive Species Program
Montana Weed Control Association – Dalamation Toadflax Project
Southwest Exotic Plant Information Clearinghouse (US Geological Survey)
Info about Dalmation Toadflax from the Washington State Government site
Author’s notes:
Dalmatian toadflax tends to spread along rivers and roadsides. It likes ground where bulldozers and dumptrucks have stripped away native plants. Toadflax (the name makes me think of an evil character from Tolkien) is frost tolerant – it gets out of the ground early, helping it crowd out slower native plants.
Dalmatian toadflax is one of a number of plants that play on human conceptions of beauty. Because of this, it has spread beyond its old home in central Eurasia to far-off lands, such as Flagstaff, Arizona, where I live.
Our local weed-control officer told me a story about a weed-pull she supervised. Young children from area schools attacked Dalmatian toadflax spreading in Grand Canyon National Park. At the end of the day, one child carefully carried an uprooted Dalmatian toadflax plant onto the schoolbus. When asked what he planned to do with it, he told the weed control officer that “I’m going to give it to my father. He loves this plant.”
One way to combat toadflax is for individuals to take it upon themselves to pull it when they see it. I’ve adopted a section of my neighborhood. I frequently pull Dalmatian toadflax while I walk my dog. I like to wait until after it rains, when the ground is soft and roots pull easily. Last summer I pulled a roadside patch 4 meters wide and 15 meters long. I know I’ll have to pull more toadflax there this spring – the weed keeps coming back.
Lowell Observatory in Flagstaff, Arizona, had a serious problem with Dalmatian toadflax. Astronomers took it upon themselves to eliminate the weed and restore the natural beauty of the native plants it had crowded out. After several years of tenacious pulling the weed still occasionally appears, but native flora has returned.
Additional Teacher Resources
Invasivespecies.gov, A Gateway to Federal and State Invasive Species Activities and Programs: Dalmatian Toadflax,
This site provides a species profile of the Dalmatian toadflax as well as links to numerous federal, state, academic and international sources for additional information.
Washington State Noxious Weed Control Board, Weed Information: Dalmatian toadflax
This site contains a brief natural history of the Dalmatian toadflax including, description, variation, economic importance, geographic distribution, habitat, history, growth and development, reproduction, and bio-control potentials.
USDA Forest Service: Yellow toadflax
Yellow toadflax is an escaped ornamental brought to this country from Europe. It has become a serious problem in some areas. This report explains the noxious weeds’ journey to the United States and the potential threat it now poses.
