Opps, I just now read your butterfly flower name: Loosestrife. Good research on your part to get it identified. Now I would not want that plant -- it is a serious invader plant. So set aside multiple white violet in a pot and I will do the same for the tiarella. I'm interested in the stream violets (yellow), but just returned from out of town and haven't researched it yet.

Hi Kayakay. You will love these little yellow stream violets. They are a pacific northwest natural. They slowly spread in shady areas to form a solid mass in early spring with cheery yellow blooms above the folage. They are in full bloom right now so you will get to see how pretty they are. They are drought tolerent, and if not watered throughout the summer they go dorment until next spring. I've had mine for 20 + years and would not be without them. I will bring you a large clump to start with, these are easy keepers without being invasive.

It's the Purple loosestrife (Lythrum salicaria) that is the wetland invader. Lysimachia punctata is not a problem. Lysimachia vulgaris is on the list. Both L. punctata and L. vulgaris have pretty yellow flowers and endear themselves to gardeners. But neither one is the kind of menace that Purple loostrife is to wetlands.

Best Regards
Jim Eichner
GreenElephant

Here is a link that might be useful: Class B noxious weeds for WA state