How to tell difference between Heliopsys and Helianthus
Out here in west central Minnesota, there is a lot of yellow flowering Heli... something and I cannot tell the difference bwtween the Heliopsys and the Helianthus. For a long time I thought it was all Heliopsys but after driving by a DNR wildlife refuge I see that there are great stands of Helianthus in bloom. I can thell these are Nelianthus because they are very tall-about 6' and have reddish stems.
But otherewise, I cannot tell the blooms apart.
Is there a quick and easy way to determine them?