I keep seeing ragwort being pulled up by people who may not fully understand the role of the plant. Many of us have been taught that ragwort is bad, but if we are going to have a wildflower areas and promote insects, we need this reconsider this plant.
Ragwort is native and is one of the most sustaining hosts to insects that we have: seven species of beetle; twelve species of flies; one macro-moth, the cinnabar with its distinctive black and yellow rugby jersey caterpillars; and seven micro-moths feed exclusively on common ragwort. Without ragwort in Boston Spa, these insects will all go locally extinct.
It is also a major source of nectar for at least thirty species of solitary bees, eighteen species of solitary wasps and fifty insect parasites. In all, 177 species rely on common ragwort as a source of nectar pollen or food. When most of the other flowers have died, ragwort continues on into late summer, providing a vital source of nectar or pollen.
But it is Poisonous!
Yes, as a safe guard it tastes and smells bad it is only fatal if livestock if they eat a lot of it and they will avoid it unless no other food is available or if it is part of a hay harvest so they cannot avoid it.
We do have many other plants that we consider OK but some are more poisonous eg.
Black and white bryony
Ragworts contain pyrrolizidine alkaloids. These are also found in Comfrey and Butterbur. http://ragwort.org.uk