It seems to be an especially bad year in terms of Tansy Ragwort throughout the mid-valley.
Here are some helpful tips from retired pasture expert Gene Pirelli at OSU Extension-Linn County.
At this stage, tansy ragwort is difficult to control with herbicides. Most likely even if sprayed it will make mature seed before it dies.
Here are a couple of options for fully-flowered tansy.
1. Cut or dig and remove. It will probably sprout again but keeps seed from being dropped. Take off the field and dispose in a separate place like garbage or covered pile.
2. Mowing will be as effective as spraying but animals need to stay off the pasture until all of the plants have decomposed. Tansy is toxic even if dry and animals tend to eat it better dry as compared to green. This is also true if herbicides are used.
3. Sheep and goats are resistant to the alkaloid but can suffer toxicity if consuming 100 percent tansy for several weeks.
You can find more resources here https://extension.oregonstate.edu/search or give our office a call and we’ll connect you with an expert.
