Some Clematis won't grow well
Hi all, I have been having some problems with a couple of my clematis. I have a Gillian Blades and a Perle d' Azure that just don't seem to want to grow more than a foot. What can I be doing wrong?
The Gillian Blades is planted where I had hoped it would scramble through some spirea bushes. It's planted well away from them so that root competition shouldn't be the cause; it gets ample sunlight and the normal water from rainfall, and is mulched. I always fertilize well with compost and bone meal when I plant and then feed them in the spring with some rose food spikes. It grows, but just barely. I thought this one should at least get a few feet tall but it really just doesn't do anything.
My Perle 'd Azure is much the same as far as conditions, but in a different bed and planted to sprawl up into my tree hydrangea. Again, planted a ways out from the tree to keep the roots from competing, plenty of fertilizer, sun and water. I have other varieties that are doing just wonderful in the same conditions, but these two just don't seem to want to grow. They don't appear diseased or damaged either. Any ideas?