Dalmatian Toadflax   CLICK HERE FOR INTERACTIVE DISTRIBUTION MAP

Description: DALMATIAN TOADFLAX — Linaria genistifolia ssp. dalmatica (L.) Marie and Petitmengin Scrophulariaceae — (Figwort family) Dalmatian Toadflax is a perennial, up to three feet tall, reproducing by seed and underground root stalks. The plant has broad, waxy, heart-shaped leaves that are dense and alternate. Flowers are borne in the axils of upper leaves. They are two-lipped, ¾ to 1½ inches long with a long spur, bright yellow with an orange, bearded throat. The fruit consists of a two-celled capsule containing many irregularly angled seeds. Early spring growth of this prolific perennial has waxy leaves with a blue-green color. Leaves individually clasp the stem. Yellow flowers with long spurs appear at midsummer with plants continuing to flower until early fall. Dalmatian toadflax was introduced from Southeastern Europe, probably as an ornamental. It is aggressive and may be found along roadsides and on rangeland where it becomes a serious problem by crowding out desirable forage.   Growth Habit: Perennial, often over 3` tall, erect. Leaves: Light green, alternate, broad, heart-shaped, clasping the stem. Stem: Branching, light green, smooth and leafy. Flowers: Snapdragon type, bright yellow, tinged with orange, to 1½" long spur, born in upper leaf axils. Roots: Vigorous, deep and extensive, creeping roots. Seeds: Numerous, irregularly angled. Other: Spread by seed and creeping roots. (Courtesy of Weeds of the West) Control Strategies: The extensive root system and the waxy leaves on the Dalmatian species make it extremely difficult to control. It tolerates dry gravelly sites very well and is at home on most of the rangeland in Fremont County. The root system is shallow and as a result it can be pulled with some degree of success. In gardens or flower beds, where herbicides would damage other plants, pulling is a good choice. It is not grazed well by any domestic animals, so grazing gives little control. Dalmatian toadflax does not like to be mowed and watered.  It is commonly found on the rough at the Lander golf course, but never in the fairway where it is irrigated and mowed, and has to compete with turf. Since turf, irrigation and mowing are not options in rangeland sites, Dalmatian toadflax has the potential to be very damaging there. Three herbicides have been used in Fremont County with good success. Tordon is very effective when applied at the rate of one quart per acre in the late summer or fall. But, Tordon use is restricted to high dry rangeland sites away from residential areas. Where Tordon can not be used, Escort, and a related product called Telar, produce acceptable results when applied at the rate of 2 ounces per acre in a high volume spray to insure complete wetting of the plant and a methylated seed oil surfactant is added at the rate of 1% volume to volume in the spray solution. The surfactant breaks down the waxy cuticle on the leaves and gets the herbicide into the plant. Where bare ground can be tolerated, glyphosate (Roundup and the generic equivalents) will killl Dalmatian toadflax, but it kills everything else and is a poor choice on rangeland sites where Dalmatian toadflax is commonly found. Biological Control: Three biological control agents have been released in Fremont County for the control of Dalmatian toadflax. Calophasia lunula has not established as far as we can tell. It is cold sensitive and must have snow cover to over winter. The small flower beetle Brachrypterolus pullicaria is established and feeds on seeds in the flower. While it does reduce seed production, this insect probably does not provide much control. The most important agent is a stem mining beetle Mesinus janthinus. Mesinus has established well and has been redistributed to all Dalmatian toadflax in the county. This beetle has virtually eliminated Dalmatian toadflax at a number of sites in the west and we anticipate measurable impacts  in 2006-07.   To learn more on biological control for Dalmatian Toadflax visit this site.

450 N. 2nd Street Lander, WY 82520 / 307-332-1052 1446 Cowboy Lane Riverton, WY 82501 / 307-856-2192 fcwp@wyoming.com