Houndstongue

As is the case of many invasive species of plants, Houndstongue is an attractive plant with pretty flowers. Its side affects however are not only that it grows everywhere with abandon, it also Kills animals that eat it.

Horses and Cows are particularly affected by houndstongue but it also can kill sheep. It also substantially reduces their values of the sheep’s wool because the burrs of the Houndstongue stick to it like Velcro.

Houndstongue contains “pyrrolizidine alkaloids”(big word) that have a cumulative affect on the liver and cause irreversible damage. All it takes is for an animal to ingest 5-10% of its body weight in the houndstongue over a period of time for this to be lethal. An animal such as a horse or cow doesn’t know it’s consuming a poison, they are just satisfying their hunger.

This invasive weed is hardy to most temperature zones and does well in shade or sun. Houndstongue grows in open fields, pastures, disturbed areas and roadsides.

More Info: Houndstongue is native to Eurasia but has rapidly spread all around the world including The United States and Canada. It is a biennial that can grow from 1-4 feet tall and spreads by producing up to 650+ seeds per plant. The seeds themselves are hardy and viable up to 3 years so they have plenty of opportunity to sprout.

Houndstongue forms a rosette the first year and is resilient enough to withstand grazing as well as severe drought. Since it is a biennial flowering occurs the second year but you’ll see flowers every year because of natural staggered seed germination patterns.

Smaller Infestations:

Hand pulling on small sites in the spring before the plants produce their seeds. You’ll need to dig 1-2 inches below the soil surface with a spade type tool to remove all the top growth. Herbicides can be used but with caution. Consult with your local county extension agent first for recommendations that suit your particular region.

Larger Infestations:

Mowing can reduce the seed production by up to 60% and also puts stress on the plant. Make sure to mow before the houndstongue has bloomed for best results. Herbicides can be used but with caution. Consult with your local county extension agent first for recommendations that suit your particular region.

Biological Control:

These methods are under development and trial. First of all, burning does not work to control houndstongue! Root Weevils, Seed Weevils, Stem Weevils, Root Beetles, and Root Flies are being observed with possible success.