The Strategy - Dalmation toadflax (Linaria dalmatica ssp.) is likely an escaped ornamental plant from Europe as it resembles ‘Snap dragons’ or ‘Butter-n-Eggs’. This noxious weed is another one of our troublesome plants due to its spreading root system (rhizomes). Dalmation toadflax is taller in height than its relative, Yellow toadflax, growing to a height of 36”. It has yellow flowers with a hint of orange on the pedals and has wide leaves that clasp around the stems. The flowers are produced on the upper half of the stems and produce small pods that contain the seeds that will shake or fall out when disturbed.
The Attack - Its rhizomes allow the plant to creep into adjacent properties. It is one of the most difficult weeds to contain due to its potential ornamental beauty. Many people do not know it is noxious until it is completely out of hand or we stop by for a visit. It is usually found in disturbed soils especially rocky or gravely locations, which adds to its spreadability as it will be taken up with the soil source and spread to other locations.
The Defense - As with the other plants that have a creeping root system, mechanical control not the first choice for control. Each time the root is disturbed it promotes stronger re-growth. Numerous herbicides are available. Combinations of Tordon 22k and/or Telar XP work best. Waiting until the plants are in the bud to bloom stage of growth seems to be the best time for treatment. There are various insects that are available to help control this toadflax. As with all biocontrol, make sure that you have a large enough patch (0.50 of an acre) of solid weeds to ensure the survivability of the colony of insects. Assist your local weed professionals by not transporting this weed in soil amendments or by taking this pretty flower home to your mommy!
PLEASE NOTE -The proper use and application of herbicides can be an effective way to control and eradicate noxious and invasive plants. Before using herbicides, always carefully follow the label and safety instructions on the label. While we recommend the use of herbicides as one of the effective tools for integrated pest management, the Idaho Weed Awareness Campaign assumes no liability for herbicide applications.
For more information, click on the link below to download the Idaho's Noxious Weeds Control Guidelines publication produced by the University of Idaho Extension.
U of I Idaho's Noxious Weeds Control Guidelines (183 KB PDF download)