failing ironweed; Vernonia fasciculata. what am I doing wrong?
I planted a Common Ironweed, Vernonia fasciculata, 3 years ago. This is the 3rd spring. Each year it gets smaller and smaller. Last year it had only 1 stem. Just now I was looking to see if it was coming back and could not find it. I started digging (carefullY!) and found the crown about 8 inches down with 4 very tiny "Nubbins" that were still alive. The roots went quite deep, at least 14 inches, and I ended up breaking them off at 12 inches. From what I've read this should be a very hardy plant. It is planted in full sun, mostly sandy soil. I water during dry spells. My tester showed the Ph to be about 6. Does anyone have any suggestions what I should do? I'd like to get it replanted soon. I've heeled it in for now. Thanks!