Any reasonably fertile, well drained soil that holds moisture well.
Yes. Plants die back to the roots in winter.
Set out tubers in spring, planting them 10cm (4 in) deep. Plants grow quite tall, and can be used to shade heat-sensitive neighbors.
Can be invasive, so use flowers indoors as cut flowers to reduce reseeding.
Harvest tubers from late autumn as required. Make sure all tubers are removed from soil by end of season.
Powdery mildew often affects plants in late summer, but does not impact yields.