You know Janet, I was wondering that myself. And because they're so tough to pull up, I've never seen the roots And they've never grown in my yard so I never had cause to dig them out with a shovel. They most often seem to grow in disturbed areas & cow/horse pastures --- places like that. Full sun. I haven't been tromping through those kind of places in a number of years & I can't remember what the bloom looks like. I never paid attention back then to any bloom on it --- I know it would not have been anything that caught my eye.