Black Eyed Susans Stand Out in my Garden

I planted two Rudbeckia "Goldsturm" last year and they grew quite tall this summer. I have some coneflowers planted behind them as I wasn't expecting the Black Eyed Susans to get so large. When I called Bachman's to ask what type of Black Eyed Susans were true perennials for zone 4, the only one they said would last was "Goldsturm". All the rest you see for sale might last two years at the most. Hopefully he is right...