I grow this plant in England, I bought it as the form Ken Astlet but I don't know if it is this form. Provided the frosts arrive late, it flowers for me, normally September / October. I have seen it at Arleigh Hall in England covering hedges in much the same way as T speciosum can. The flowers and top growth will survive light frosts. The tubers like light humus rich soil and always form on or near the surface. It survived last winter which was unusually cold here at -20 C and is growing well. I never got it to advance to flowering untill I put it in a warm open and sunny position. In a cooler more shelterd position it just makes lots of leaf here.