Golden Coreopsis has grown out of control in my garden. They were 1 foot tall when I put in the original plants 2 years ago. Last year I didn't have any at all - some garden helpers pulled them out in early spring thinking they were weeds. But this year they are back with a vengeance - a towering 4 feet tall, growing over all my other perennials and shrubs. So I am enjoying the show they're putting on, and then I plant to pull them and let them reseed in a more appropriate place where they can grow to their heart's content!
Golden Coreopsis, Coreopsis tinctoria
This amazing wildflower gets 1-4 feet tall. The yellow and reddish/brown leaves are bright and bold, made even more so by the giant stems on which they rest.