The roots will grow to a depth of 15 or more feet. The seed are propelled 15 feet from parent plant when the three celled capsule matures. Canada thistle has an extensive, creeping root system. Root buds will come from depths of 3 feet or more to emerge and produce more plants for seed production. The leaves of Canada thistle are many lobed with spines on the ends of the lobes.
Spines are absent on the stem.
When mature the flower petals form a plug over the seed head and as it tumbles this plug comes out and the seed is dispersed. Deep rooted with numerous root buds make it very difficult to control. This plant is an aggressive invader if not kept in check. This is a perennial plant that spreads by seed and root stalks. The extensive root system with waxy leaves make it hard to control.