Sonchus kirkii
Other species of weeds that grow more quickly might be the reason for the shore puha to be at "declining" because it is not as good at growing as the other plants. The plants Sonchus asper and Sonchus oleraceus can take over the habitats that the shore puha likes and grow in the area faster. Until the 1980s the shore puha was not in danger, but after that the amount of shore puhas left have been going down.