Jackmanii in poorly drained soil
I am a novice gardener. I planted a young Jackmanii clematis at the end of April. It gets a lot of sunlight and I have watered it religiously. However, it has only grown about 6" up the trellis (it was about 2' high when I purchased it and had no blooms yet) and only one sad flower has appeared. After learning more about the plant, and my soil, I fear that the soil it is in stays wet and is poorly drained. I have been thinking about raising the bed it is in and adding about a foot of good soil. If I dig up the clematis and replant it in the 1' of good soil, will this help it? Does this sound like a reasonable plan? Is the poorly draining soil the likely culprit for why this isn't growing or flowering?
Thank you for any advice.