Fair warning, this plant is hearty AKA it does spread but it is easy to control; I simply pull up any runners that I do not want and the main clump remains compact and upright. I have had this plant in the garden for three years and it has never had any issues with disease or pests and it does not get 'bald' in the middle like some clumping plants do. I plant mine with Verbena bonariensis, coneflower and moonbeam coriopsis.
Mine is in the part sun, in rich soil and I do water regularly.
Common Name: Gooseneck Loosestrife
Hardiness Zone: 3-8 S / 3-9 WHeight: 36"
Exposure: Full or Part Sun
Blooms In: July-Sept.