Who wouldn’t want a green dragon in the garden? The problem is that some green dragons are native to North America (Arisaema dracontium) and others are not (Pinellia Pedatisecta). Pinellia is commonly sold as Arisaema dracontium, and since Pinellia is much more aggressive it can take over native areas after well intentioned gardeners plant it.
If you grow either of these plants, make sure you know which one you have.
There is nothing wrong with growing Pinellia in North America; just make sure you label it correctly, and don’t plant it in wild areas.