Linaria vulgaris.
Butter-and-Eggs Toadflax. |
Dalmatian Toadflax
Butter-and-Eggs or Yellow Toadflax
(Linaria dalmatica and Linaria vulgaris)
Traditionally in the Figwort family, taxonomists reclassifed Linaria as part of the Plantain family based on genetic evidence.
About Toadflax: The name Linaria was coined in medieval times, meaning "looks like Linum, flax." dalmatica refers to Dalmatia on the Balkan Peninsula. vulgaris means common. Toadflaxes are native to Europe and Asia. Butter-and-eggs toadflax was imported from Wales to Delaware by the Quakers, who cultivated it as a garden flower and medicinal herb. Dalmatian toadflax was introduced to the western U.S. as an ornamental about 1874. The leafy plants of some species look much like the unrelated flax plants, and someone thought the flowers resembled toads, hence the name "toadflax."
Linaria vulgaris.
Butter-and-Eggs Toadflax. |
The toadflaxes first appeared in Montana in the 1940's, and they have become widespread since then. Like many other invasive weeds, toadflax thrives in dry, exposed soils on rangeland or along roads. Toadflax seedlings are poor competitors for soil moisture, but once established the plants develop a vigorous spreading root system. New plants develop from the root buds or from seeds. A single plant can produce a half million seeds. The plants live for about five years and the seeds remain viable in the soil for up to ten years. Bees love them.
Traditional Uses: Medicinally, Linaria vulgaris is reported to be astringent, bitter and acrid, useful to stimulate liver function, or as a wash for skin diseases. According to Dr. Larry Mitich in The Intriguing World of Weeds, Europeans made "a lotion that was unparalleled for insect bites. Toadflax lotion was a popular English tradition and there are many references to it in New England records. And before the introduction of screen doors, window screens, and flypaper, yellow toadflax was used to fight the swarms of flies that tormented settlers. The plant was boiled in milk which was set out in saucers to poison flies. This use probably originated in Sweden."
Butter-and-eggs toadflax has been cultivated as a garden flower and a dye crop for centuries in Europe, especially in Germany. Immigrants were glad to find the herb already established in America, and they cultivated fields of it for dying homespun fibers for clothing.
Linaria vulgaris, gathered just as it comes into flower, is still used in preparations for for jaundice, liver troubles, and various skin diseases. [Mitich]
L. vulgaris has been used traditionally in for its astringent, laxative, diuretic, emollient, litholytic (calculi-dissolving), anti-cancer, anti-hepatitis, anti-jaundice, liver-assisting, piles-removing, anti-scrofula, wound-healing, inflammation-of-the-spleen-assisting properties. [Dr. Duke's Phytochemical and Ethnobotanical Database]
Linaria dalmatica.
Dalmatian Toadflax. |
Mechanical Controls: Small patches of toadflax can be hand-pulled for five or six years to deplete the energy reserves of the root system. The University of Nevada Cooperative Extension says: "Pulling or cultivating young Dalmatian and yellow toadflax plants in small infestations before they go to seed will provide control, even eradication, if done consistently for several years.The site will need to be revisited... several times per season to completely eradicate these toadflaxes if pulling, plowing or cultivating is used for control." [University of Nevada Cooperative Extension]
It is important to remove the lateral roots completely, since root fragments can survive to grow new plants. Viable seeds in the soil may continue to germinate for 10 to 15 years. Mowing reduces seed production, but does not deplete the root system, and in fact can encourage the plants to spread horizonatly via the roots and send up additional stems. Therefore, mowing is not recommended as a method of control. Frequent cultivation can work (multiple passes per year), but generally isn't recommended, since the broken root fragments grow to become new plants, exacerbating the problem.
Biological Controls: Two insects are already widely distributed on toadflax infestations across the northern states and Canada. A small black beetle (Brachypterolus pulicarius) damages the tips of the shoots, preventing many of the flowers from developing. The insect can reduce seed production by up to 75%. A fruit-feeding weevil (Gymnaetron antirrhini) feeds in the flowers and reduces seed production by up to 80%. These insects may slow the spread of the toadflaxes, but may not reduce the size of existing infestations. Other insects that have been introduced to control the toadflaxes include two root-boring moths (Eteobalea intermediella and Eteobalea serratella) a root-galling weevil (Gymnetron linariae), another fruit-feeding weevil (Gymnetron netu), a stem-boring weevil (Mecinus janthinus), and a moth that feeds on the leaves and flowers (Calophasia lunula). There is a concern that this moth could attack native snapdragons of California, so redistribution of the insect is now discouraged.
Linaria dalmatica.
Dalmatian Toadflax. |
Grazing: Livestock and wildlife do not favor toadflax, but they do browse on it some. There is little documentation available on the impacts of either grazing or trampling the plants. However, since the seedlings are poor competitors for soil moisture, trampling may stimulate other plants to out-compete them. Caution is advised if the plants are grazed while producing seed. The seeds could be passed through the manure and spread to new habitat. More studies need to be done with livestock on these weeds.
Chemical Controls: The toadflaxes are hardy plants with waxy leaves and extensive root systems. Even the most potent herbicides have mixed results. Herbicides that have been used with some success include dicamba (Banvel®-pre-bloom), chlorsulfuron (Telar® DF-spring or fall) and picloram (Tordon® 22K-pre-bloom or fall.), but repeat applications are required to achieve full control. Spraying is reportedly most successsful at the beginning of flowering when carbohydrate energy reserves in the roots are lowest. Spot applications of glufonsinate-ammonium (Finale®-spring) or glyphosate (Roundup®-fall) may be more effective and less hazardous.
Important: Most "weed problems" are really "people problems" from poor land management and a lack of ecological insight. It is easy to reach for a tool like fire, mowing, or herbicides to attack an out-of-control weed, but often those tools do little to get to the root cause of the weed infestation, and sometimes make the problems worse. Please read more about range ecology, desertification, and invasive weeds on this website before applying any tool of weed control Go to: Desertification and Invasive Weeds.
Notes
- Thomas J. Elpel. Botany in a Day. HOPS Press: Pony, MT. January 2000.
- Rich Hansen, USDA-APHIS-PPQ, Forestry Sciences Lab, Montana State University, Bozeman, MT 59717-0278: https://www.nysaes.cornell.edu/ent/biocontrol/weedfeeders/toadflax.html
- Sherry E. Lajeunesse, Peter K. Fay, Diana Cooksey, John R. Lacey, Robert M. Nowierski, and David Zamora. "Dalmatian and Yellow Toadflax: Weeds of Pasture and Rangeland" MSU Extension Service Bulletin EB 115. 1995. Reprinted May 1998.
- Larry Mitch. "Yellow Toadflax." The Intriguing World of Weeds. https://wssa.net/wp-content/themes/WSSA/WorldOfWeeds/yellowtoadflax.html.
- _____. "Dalmatian Toadflax: Guide to Identification and Control in Western Montana." USFWS.: Moiese, MT. April 2000. Vol. 1.
- Dr. James Duke's Phytochemical and Ethnobotanical Database https://www.ars-grin.gov/cgi-bin/duke/ethnobot.pl
- University of Nevada Cooperative Extension: https://www.unce.unr.edu/publications/files/nr/2002/fs0296.pdf
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