Tansy isn’t very common in the UK. It tends to grow in clumps and the clumps are often quite far apart along a riverbank. Cattle like eating it and can destroy a clump by grazing on it.

Tansy Plant

Tansy is sometimes mistaken for ragwort and pulled out by farmers because ragwort is poisonous to cows and can also make sheep and horses very ill. It only really likes growing on disturbed ground and so often won’t stay growing in the same place for a long time. More recently it has been outcompeted by the invasive plant Himalayan balsam, which has a wider habitat spread and is less specialist than tansy.