Field Guide     Weed Management     Toadflax

Toadflax (Linaria vulgaris Mill)

Crop Impacts: Pastures

Toadflax 1

About Toadflax:

The Toadflax is a perennial weed, which not only reproduces by the release of their seeds, but also by their creeping roots that produce new shoots typically forming very dense infested patches.

Toadflax Scouting and Prevention:

When scouting for Toadflax keep an eye out for an erect stem that stands from 20 to 90 cm tall, with branching in the upper half, and with the entire plant smooth and hairless. The leaves of the Toadflax are very narrow, with so many leaves on the weed it may look like the leaves sit opposite of each other, this is not true, and they sit one per node. The yellow flowers of a Toadflax have an orange spot on the lower lip of the petals, and flowers from June to autumn. Each flower lives on the end of a short-stalk, with 2 lips at the top that have to lobes and long spurs at the lower side, with 3 large lobes on the lower lip of the plant. The seedpods are egg-shaped holding numerous black to dark brown, flat and winged seeds.

Common locations

  • - Moist soil
  • - Cultivated fields
  • - Along fence lines
  • - Pastures

Prevention

Prevention of Toadflax is less expensive and less time-consuming than trying to control it. Make sure when you are seeding a new area you are doing so with certified weed-free seeds. If there is an infested area on your property, be sure to drive around it, instead of through it. Finally, make sure to give all equipment that has been in infested fields a good clean, to ensure that no seeds are transferred.

Toadflax Control:

Cultural Control

Frequent tilling that is started right after harvest and continues into the next summer will control Toadflax in your fields. It is important that you do not allow the plant to stay above ground for more than 5 days. Making sure you have a good crop rotation is extremely important in keeping Toadflax under control. Adding a winter annual cereals into the rotation with summer fallow and cereals are especially effective. If you plant crops like wheat or barley, which are able to compete with Toadflax, they can be important parts of your rotation.

Chemical Control

There are a few herbicide controls that will work in the eradication of Toadflax. 2,4-D amine applied at 4.4-9 L/ha yearly has been shown to reduce infestations. Amitroal-T (amitrole) that is applied at 22-35 L/ha in 500L of water can control Toadflax. Tordon 22k (picloram) applied at 9L/ha provides good control on permanent pastures. Applying Roundup (glyphosate) on early bud stage of Toadflax at 7 to 12 L/ha works well. For this particular herbicide application, wait at least 7 days before you start tilling sprayed area.

Latin / Alternative Toadflax names:

  • - Linaria vulgaris Mill
  • - linaire vulgaire
  • - Butter-and-eggs
  • - Common toadflax
  • - Yellow toadflax
  • - Wild snapdragon
  • - Linaire commune

Additional Toadflax Resources

http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/toadflax.htm

http://www.weedinfo.ca/en/weed-index/view/id/LINVU

http://www.agriculture.gov.sk.ca/Default.aspx?DN=925fc846-1523-4125-8c0e-cf56adb58d37