Common name: Dalmatian toadflax, broadleaf toadflax, and wild snapdragon
Scientific name: Linaria dalmatica (L.) P. Mill. ssp. dalmatica
Related species: Yellow toadflax, Linaria vulgaris (L.) P. Mill
Dalmatian toadflax is an early detection target species. Information on reporting Dalmatian toadflax infestations.
Minnesota is fortunate to have very few Dalmatian toadflax infestations. The goal is to eradicate infestations before Dalmatian toadflax spreads and becomes a serious weed issue in our state. Dalmatian toadflax is native to the Mediterranean region and was originally introduced as an ornamental to the west coast of North America in the late 1800s. It escaped cultivation and has overtaken grasslands in pastures, rangelands, and natural areas in the west. As a result, western infestations have reduced livestock production, land values, biodiversity, and wildlife habitat.
Dalmatian toadflax looks like a large, yellow snapdragon. It is a short-lived perennial that grows up to 4 feet tall. Both leaves and stems are a waxy, bluish-green. Leaves are heart-shaped, 1 to 3 inches long and clasp the stem. Multiple flowers are arranged in spikes on the stems. They are bright yellow and sometimes have an orange center. The flowers are 1 to 1½ inches long and have spurs. Flowering occurs from early summer to early fall. Seed pods are ½ inch long and contain 140 to 250 small dark brown to black seeds with wings. Most of the upper stems die back in winter and new stems emerge in the spring.
Yellow toadflax is common in Minnesota and looks similar. To distinguish the two species, compare the small, narrow, linear yellow toadflax leaves to the thick, waxy, clasping, heart-shaped Dalmatian toadflax leaves.
Dalmatian toadflax prefers sunny areas with well-drained often coarse-textured soils. These areas can include roadsides, pastures, residential areas, cemeteries, gravel pits, and waste areas.
Dalmatian toadflax can quickly colonize an area because it spreads by sprouts from the lateral roots and by seed. Over its lifetime, a single plant can produce up to 500,000 seeds that can persist in the seedbank for up to 10 years. Dalmatian toadflax flowers have both male and female parts and the species is self-compatible meaning that a single plant can produce viable seed and start an infestation. Seed dispersal begins shortly after flowering and continues into winter. Dispersal can be by wind, water, wildlife, vehicles and equipment, forage, and livestock.
Most Dalmatian toadflax infestations are in western states. In these areas, Dalmatian toadflax has increased at a rate of 8-29% per year depending on the site. In Minnesota, there is a confirmed infestation in Kittson County in the far northwestern part of the state and herbarium specimens were collected at sites in Cook and Cass Counties in northeastern and north central Minnesota respectively, but there are not confirmed infestations at these locations. (View Dalmatian toadflax distribution)
Prevent seed from moving with hay, vehicles, and equipment from infested areas, mostly western states. Also prevent seed movement with gravel from infested pits.
For existing infestations, develop a long-term, site-specific management plan. The seedbank can persist for up to 10 years so management practices must be implemented repeatedly as the infestation regenerates from the seedbank.
Dalmatian toadflax is a prohibited noxious weed on the eradicate list. This means that all of the above and below ground parts of the plant must be destroyed, as required by Minnesota Statutes, Section 18.78. Additionally, no transportation, propagation, or sale of these plants is allowed.
Dalmatian toadflax contains an iridoid glycoside, a quinoline alkaloid, and a peganine so it is toxic to some livestock such as cattle. However, cattle avoid Dalmatian toadflax and there are no confirmed reports of livestock poisoning.
Minnesota Department of Agriculture (MDA), 625 Robert Street N, St. Paul, MN 55155-2538, firstname.lastname@example.org