Willow & Max Sunflower (IMAGE) American Society of Agronomy Caption Maximilian's sunflower and big bluestem (foreground) were two of the eleven species planted in the native polyculture treatment. Photo shows the willow-native polyculture treatment at Granada, MN in September 2013. Credit Photo credit Joshua Gamble. Usage Restrictions Please use with story only. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.