Apparently the plant is tolerant of just about any soil type, as long as it is not salty. I planted mine on a slope that is mainly clay, rock and sand. Even though I read that this plant wouldn’t mind that poor soil, I augmented the ground aggressively with planting mulch mixed in with some potting soil. I added the potting soil because I was looking for some water retention on the slope. I also inoculated the roots with micorriza which should help the plant obtain more nutrients and moisture.
Moderate water needs due to its naturally deep root system. However, you should err on the side of over watering during the first month or so after planting. I have also read that this plant can tolerate standing water so it should be forgiving of over watering.