Agastache foeniculum. Anise Hyssop.
A plant native to the US and Canada. An upright perennial with blue/purple flowers. It is found in prairies and wood edges. Agastache is very attractive to bees and other beneficial insects. The leaves have a nice, anise scent that can be used as a beverage tea. Native Americans use this plant for other medicinal purposes.
The native variety gets quite tall and re-seeds. This is very beneficial for filling in a native plant garden. You can limit the size by cutting back 1/3 in early to mid-June in Minnesota. A nice cultivar is A. foeniculum 'Blue Fortune'. It is more clump forming and may be more suitable for the garden border. I cut this plant back 1/3 in early to mid June to keep it sturdy and more compact. Disease and insect resistant, and drought tolerant, this is a hardy plant in full sun and a well drained soil.
Leave this perennial up for winter interest and bird forage, and cut down in early spring to the new basal foliage.