Another name is Allium albopilosum. I have thousands and will probably have some at our auction and plant sale on July 31st in the Garden Clubs Center between Highland High School and Sugarhouse Park . I am digging as many out now as I can but leaving a bunch for the sale. They have been seeding for more than 40 years. Cut off the flower heads before they go to seed unless you want a lot more. By the way they do grow in partial shade. They do grow taller than you have so you might have moved them later than optional. An ideal time to dig would be late July through August before they start to put out their new roots.
