Dear Lynn, the pennyroyal is an endangered species in America. For some reason it likes our very clean water ways, and mild but damp weather, not that it is bothered about damp as it is a water plant.
It takes the oxygen out of the water and completely clogs up even large rivers, to the point that even small fish cannot get through. There have been a lot of animal deaths already due to it, as it looks solid, and of course the Authorities are worried that in the spring they do not want human and especially children fatalities due to it. As children would try to cross over it not knowing there is in fact a stagnant river underneath it.
The reason I put it on for you is because in Yorkshire where we have lots of wild Semp. colonies in the dry stone walls, by clogging the rivers this pennyroyal has damaged whole ecosystems. The small streams that bring nutrients down from the mountains and pure water are getting clogged up with this pest, the small rivers and streams are like the main arteries to where the Semp. and our carnivorous plant stands are. Cut the arteries off and these wild plant areas are in danger.
All this because someone thought they would get someone to send them a bit of this dre4adful plant so he could have it as an ornamental plant in his pond. What an idiot, don't play god with nature, it bites back.
Hope you all are recovering after Thanksgiving Day?
Kindest regards to all from a wet England.
Neil.
