Toadflax

Above left and right - Dalmation Toadflax

Left and below - Yellow Toadflax; Right - Butter and Egg Toadflax

Linaria vulgaris Mill., yellow toadflax, linaire vulgaire

A spreading perennial, toadflax has become a nuisance in the coulees of Lethbridge.  So much so that volunteers are in the coulees manually pulling them out.  Toadflax spreads by seeds and underground roots.  The pretty yellow, yellow with orange throat or white with yellow flowers grow on stems 6 inches to 2 feet (15 cm. to 6 dm.) high.  They grow in grasslands, cultivated fields, gardens, roadsides, and waste places and I've admired their blooms here in the nearby ravine.  They were introduced from Europe and Asia.
 
The bad news is this pretty little plant is a weed that is choking out desirable vegetation that local wildlife in the Lethbridge area depend on for food.  On that note, it has been decided not to use herbicides because of their effect on wildlife thus volunteers are manually removing them.  This plant can release 500,000 seeds per plant!  Talk about fertile!