Shame you aren't in Montana or I could give you a bunch. Very invasive. Can't be controlled with chemicals. You can dig it and dig it and miss a tiny root and it will come back. Be sure to put it in a place that won't matter if it spreads. It will make a big mat and grows at least 2 feet tall. I am sure you will find some as all old homesteads had it and used it medicinally. There can be some problems if not used correctly.

Nichols Garden Nursery (online)

Thank you so much! I did find some at Nichols.

Best wishes!