Tackle Tansy Ragwort Day - July 7, 2019

July 7th , 2019 has been declared Tackle Tansy Day!

Tansy ragwort (Senecio jacobea) is a member of the aster family. During the first year of growth it forms a ground-hugging rosette of lobed leaves, in the second year it shoots up to it’s full height of up to 1.2 m (4 ft). Usually it will die after flowering but can become a short-lived perennial. You might ask how a plant with such a short lifespan can become a huge problem….each plant can produce up to 150,000 wind-blown seeds which can remain viable for up to twenty years and the dense root system can displace agricultural forage and native species, reducing pasture production by over 50%.

Horses, cows and goats that ingest tansy ragwort can suffer liver damage which can lead to poor condition and death. Apparently most poisonings are the result of eating small quantities over an extended period, the effects accumulate over time. Effects are worse on young animals.

 “Symptoms include depression, loss of appetite, chewing of fences and dirt, restlessness and wandering aimlessly, walking into fixed objects, yellow or muddy discolouration of mucous membranes and an unpleasant pig-like skin odour. In severe cases serum will seep through the skin due to a photosensitive reaction resulting from liver damage”.

The highest concentrations of the toxic alkaloids occur in the flowers and dilute forms of the poison have been found in honey and milk products. Although the potential risk to humans is considered very slight, caution should be observed when using these products over the long term.

Tansy Ragwort’s bright yellow blooms make them easy to spot and remove. A number of people throughout Metchosin have taken it upon themselves to uproot every plant they find. The plants have a shallow, fibrous root system, which makes them easy to dislodge. Wear gloves and dispose of the flowers in a garbage bag. By this time of the year, even uprooted plants might continue maturing the seeds and the flowers at least should be bagged and sent to the dump.

Three biological agents have been released to help control the spread of tansy ragwort, the most conspicuous is the beautiful red and black cinnabar moth, which flies in June and July, laying it’s eggs on the plants. The striking yellow and black striped caterpillar can defoliate a plant but they don’t appear to be reducing the plants’ rate of infestation. As well, the caterpillars are apparently toxic to our native alligator lizards. A seed head fly and a root eating flea beetle have joined the control arsenal and the root beetle seems to be making some headway in reducing populations.

It is thought that the plants were originally brought over from the British Isles as a medicinal herb, but as in many cases, too much of a good thing can have the opposite effect.


Monday, June 3, 2019 - 1:30pm