I wish you could have gotten more organic material into your clay before you planted your cutting...it doesn't sound like you have it in ideal conditions for surviving, but plants don't always follow the rules and hopefully it will surprise you.

Roots of this genus are fibrous and fine-textured and normally are unable to extend into dense hard soils. Best is lightweight, porous, well-drained but moist soil.

What could help and is free - compost. It aids in aeration and drainage of heavy soil the same way it improves sandy. Unfortunately, compost isn't always immediately at our fingertips when we need it, but if you don't have your own, Home Depot here has a well composted (and weed-free) steer manure mix for just $1 cubic foot bag. While best would be to get the organic material into the soil before planting, top dressing with it will help to condition and improve soil over time.