Dalmation Toadflax - Linaria dalmatica

Description: Dalmatian toadflax is a perennial forb with a large taproot, waxy, fleshy leaves, and a showy spike of bright yellow flowers.

Type: perennial

Habitat & Impacts: It can grow in a wide range of habitats from gravelly disturbed roadsides to open forests. Infestations of Dalmatian toadflax can reduce forage quality and quantity for livestock and can reduce native vegetation cover in areas of severe infestation. Toadflax can displace sod-forming or bunchgrasses and increase soil erosion, surface runoff and sediment production (Lajeunesse 1999). Cattle may occasionally graze toadflax flowerstalks but this may lead to mild poisoning and usually cattle avoid this species. Sheep will graze toadflax without apparent ill effect.

Method of Spread: Dalmatian toadflax reproduces by seed or can spread vegetatively from the roots. Each plant can produce a very large number of seeds, up to 500,000 per plant, but most seeds land close to the parent plant (Robocker 1970). However, birds and mammals may eat Dalmatian toadflax seedheads and spread seeds a considerable distance. Dalmatian toadflax seeds may remain viable in the soil for up to ten years. Dalmatian Toadflax can also spread by creeping roots.

Location: Throughout region except the Coast and Nazko. Scattered throughout the Chilcotin, and heavily present in the Tatlayoko valley.

Management Options:

Mechanical Control: Mechanical treatments consist of: Cutting plants prior to seed set to control seed production, repeated disking or tilling in cultivated fields over several years to reduce or eliminate infestations in cultivated fields or hand pulling prior to seed set to control small infestations.

Chemical Control: Chemical treatments in the Cariboo Chilcotin Coast consist of a fall application of picloram or picloram/2,4-D to control toadflax infestations in areas that do not have a successful bioagent catch. Dichlorprop may also been used in this region.

Biological Control: Mecinus janthinus, a stem weevil has been used with great effectiveness in the Cariboo. Many sites in the region have declined or been eliminated in recent years due to the successful establishment of the biocontrol agent. There are areas in the region, particularly the Chilcotin, where biocontrol agent releases in the past were not successful. A large biocontrol release in 2007 is being monitored in the Tatlayoko Valley and the management strategy will be re-evaluated if biocontrol proves unsuccessful. Other seed eating biocontrol agents are being developed.

CCCIPC Priority & Treatment Strategy: Priority 1 (new invader) in Nazko and Central Coast , Priority 2 in Chilcotin (containment), Priority 4 for all other areas (biocontrol)

Treatment Options:

Local Level – Handpull or cut.
Landscape Level – biocontrol releases, and chemical treatment on localized areas such as private land.

Dalmatian Toadflax plant in flower

Dalmatian Taodflax flower

Mecinus janthinus, stem and leaf weevil biocontrol agent

Linda Wilson, University of Idaho, Bugwood.org


Invasive species profile taken from the Cariboo Chilcotin Coast Invasive Plant Committee Invasive Plant Regional Strategic Plan

Page last modified: October 30, 2018 09:44:02 PDT