Scrophulariaceae or Figwort Family
Growth Habit: Perennial, often over 3 feet tall.
Leaves: Light green, alternate, heart shaped, clasping the stem, waxy.
Stems: Branching, light green , smooth with many leaves.
Flowers: Like snapdragon, bright yellow, 1.5 inches with long spur.
Roots: Vigorous, deep and extensive, rhizomatous.
Seeds: A single plant can produce up to 500,000 seeds. Seeds are viable for at least 10 years or more.
Reproduction: Vegetative bud, root stock, and seeds.
Habitat: Found in meadows, roadsides, native grasslands, pastures, and waste places.
Handpulling: May only be effective on extremely small infestations that have not yet established an extensive root system. For all other infestations handpulling is not an effective method of control.
Mowing: Due to the extensive root system, mowing is not a recommended method of control, though it will reduce seed production if repeated often enough to prevent flowering.
Biological Control: There have been six bio-control agents released in the U.S. for the control of toadflaxes. Of those, only one is readily available and known to be well established in Montana. Mecinus janthinus is a stem-boring weevil that feeds on the leaves as an adult and lays eggs in the stem, where the larvae develop and feed. Contact the Missoula County Weed District for assistance with monitoring and/or additional releases.
Grazing: Sheep and goats can be trained to feed on Dalmatian toadflax and have been shown to consume nearly 90% of the vegetative matter, drastically reducing seed production but increasing overall toadflax density in the infestation from re-sprouting rhizomes. The seeds of Dalmatian toadflax will pass through the systems of grazers unharmed, so be sure to contain animals for at least five days and feed them weed-seed free forage before moving them to an uninfested site.
Herbicide: Herbicide treatments are highly variable due to a thick, waxy covering on the leaves, creeping rhizomes and long-lived seeds. Timing of herbicide applications may also play a large part in successful herbicide control. The following herbicides are labelled for control of Dalmatian toadflax. Always consult product labels and read them carefully to ensure correct species/land management usage and chemical application.
|Trade Name:||Active Ingredient:||Rate:||Efficacy:||Comments:|
|Plateau||imazapic||12 oz/acre||most effective if applied in the late fall|
|Escort||metsulfuron||1.5 oz/acre||can control toadflax for up to 3 years; applied fall or spring||Cannot be used near wells, surface water or shallow ground water|
|Tordon 22k||picloram||1-2 qts/acre||most effective when applied in spring up to early bloom||
Cannot use near surface water, shallow water, landscaped areas and current or future vegetable gardens