I have a Clematis planted next to my brick house that hasn't bloomed in 3 years or since it was planted. It is in a clay soil but I have enhanced the soil but am afraid to harm the roots as I know they tend to be touchy. It's growing fine and is trellised, I have composed it and I feed it 20-20-20 fert. What on earth am I doing wrong? It also gets midday and all afternoon sun. My neighbors have theirs on the west side and its blooming fine. Other neighbor has theirs facing east and theirs is blooming great. I have been waiting 3 years now. I am almost ready to give up.. I'm in zone 5 SE Wisconsin. USA I just wanna know.