Californian thistle is one of the most common thistle species in New Zealand. It is very troublesome in pastures because it is so difficult to control. Once a plant is established in pasture, it forms ...

They produce abundant seeds, plus spread through their roots [rhizomes]. "New plants pop up from the roots, so where you had one Canada thistle last year, you might have 30 this year, and they are ...

As with most thistles, Scotch thistle has a tap-root. However, it is the only thistle species in New Zealand that has spines on the foliage on the surface of leaves in addition to around the leaf ...

For more information visit Midwest Invasive Species Information Network (MISIN). Canada thistle forms extremely extensive root systems that need to be repeatedly damaged to keep them from growing back ...