Dalmatian toadflax (Linaria dalmatica (L.) Mill.)
Dalmatian toadflax, a member of the snapdragon family, was introduced to North America as an ornamental plant and is now listed as a noxious weed in Wyoming. It spreads aggressively in rangelands, roadsides, and disturbed sites.
Dalmatian toadflax is an herbaceous perennial that produces primarily erect stems reaching up to 3 feet tall, though some stems may grow prostrate along the ground. Stems are woody at the base and waxy and herbaceous toward the top. Foliage is blue-green to gray-green in color.
Leaves are lanceolate to broadly heart-shaped with smooth margins and a thick, waxy texture. They are arranged alternately and clasp the stem. Even at the rosette stage, Dalmatian toadflax can be distinguished from Linaria vulgaris (yellow toadflax) by its broad, heart-shaped leaves.
Flowering occurs from late spring through late summer. Flowers resemble snapdragons and are borne in racemes at the ends of stems. Each flower is bright yellow, ¾ to 1½ inches long, and has two distinct “lips.” When opened, an orange, bearded throat is visible. A long spur extends from the back of each flower.
Dalmatian toadflax has both a deep taproot and spreading lateral rhizomes, allowing it to form dense colonies. Seeds are produced in two-celled capsules and are small, dark brown to black, irregularly shaped, and may have small wings.
This species produces quinazoline alkaloids and may be toxic to livestock, though it is generally avoided by cattle and horses. Goats and sheep have grazed Dalmatian toadflax without apparent adverse effects.
Quick ID Guide
Life Cycle:
• Perennial
• Spreads by seed and rhizomes
Height:
• Up to 3 feet tall
Stems:
• Woody at base
• Waxy upper stems
• Erect or sometimes prostrate
Leaves:
• Blue-green to gray-green
• Broad, heart-shaped
• Smooth margins
• Waxy
• Clasp the stem
Flowers (Late Spring–Late Summer):
• Bright yellow
• Snapdragon-like
• Orange bearded throat
• Long spur
Roots:
• Deep taproot
• Lateral rhizomes
Seeds:
• Dark brown to black
• Produced in capsules
Management Options
Prevention and cultural control strategies should be emphasized whenever possible.
​
For small infestations or plants growing in cobble or loose soil, hand pulling and digging can be effective if the entire taproot and all lateral roots are removed. Extreme care must be taken to prevent regrowth from root fragments. Tillage is strongly discouraged, as it can fragment and spread reproductive roots. Mowing is not recommended because it stimulates root and rhizome growth. Intensive grazing with goats may help suppress populations when integrated with other control methods.
​
Large infestations or areas where manual removal is impractical may require herbicide applications. Spring treatments can prevent flowering and seed production, while fall treatments may improve control by targeting the root system. Always read and follow herbicide label instructions before application. Contact Sublette County Weed & Pest for assistance with product selection, rates, and timing.
