Ya, I think you'll need to search out an early finishing plant.And certainly, start seeds early indoors.They will not have to be forced to flower.You may need to watch at the end of flowering for any killer frosts, and protect plants if needed.I'm in Mich. and we can get well into Oct. here in Lower penisula.
BE ADVISED, the way these are found in Mich anyway, is by recon flights, don't plant large areas, and be warned these stay green when all other vegetation has dropped around them.