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Yellow toadflax

(Linaria vulgaris Mill.)

Native Range: South-central Eurasia

History

Yellow toadflax was introduced to North America as an ornamental plant. It is still sold today in nurseries and seed catalogs as "Butter and Eggs" or "Wild Snapdragon". Be aware of what species are included in wildflower seed mixes, always look on the back of the product container for a listing of what's included in the mix. If toadflaxes are listed, PLEASE DO NOT buy that product.

Yellow Toadflax

Identification

Yellow toadflax is a perennial with stems that grow from one to three feet tall. The pale green leaves are narrow, linear, and pointed at both ends. Flowers are bright-yellow with an orange center, with a spur that is approximately as long as the rest of the flower combined. Flowers occur in clusters near the ends of the stems, becoming more widely spaced along the stem as the season progresses. Seed capsules are round, and two-celled. Seeds are small, brown or black, circular, and surrounded by a notched wing.

Biology

Yellow toadflax typically emerges around mid-April. Flowering occurs from May through August, with seeds maturing from July through October. A mature plant can produce up to 30,000 seeds annually a single stem has been reported to contain over 5,000 seeds. Seeds can remain dormant in the soil for up to ten years. Yellow toadflax can reproduce both by seeds and vegetatively. It can aggressively form colonies through adventitious buds from creeping root systems.

Habitat and Distribution

Yellow toadflax can be found in well-drained, coarse-textured soils but can also be found in heavier soils as well. Sites where yellow toadflax can establish include roadsides, riparian areas, dry fields, grainfields, waste areas, gravel pits, pastures and rangeland, vacant lots, and railroad yards. In Adams County, yellow toadflax infestations can be found along the South Platte River, along Clear Creek, and in various lakes and ponds.

Impacts

From seed distribution to creeping root systems, yellow toadflax can aggressively form colonies. These colonies can push out native grasses and other perennials, thereby altering and simplifying the species composition of natural communities and reducing forage production for livestock and wildlife. This in turn reduces rangeland value and can lead to erosion problems.


 

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