Not hardy? How cold does it get in michigan??
I know that the common buttercups here (Ranunculus acris and Ranunculus repens) can easily tolerate zone 4 temps, down to -35°C (-31°F). We often have -20°C in the winter, and those plants are always some of the first to appear once it warms up. R repens is a nightmare to remove. It's all over my veggie garden, and it keeps on putting out runners, very deeply rooted runners. I pull up everything every spring, but I always miss a few pieces and they're back with a vengeance the next year. R acris is much better, it doesn't spread. There's a bunch growing wild in a wet spot of the yard.
Hybrid Mode
