It like a soil rich in organic matter, moisture retentive and free drained. It is happy in light shade or full sun and even though you are in Devon, I would mulch it heavily in winter with a thick layer of bracken or similar to protect the crown.

If growing in a pot, bring into a sheltered spot in winter or the rhizome and roots will perish if frozen.

H. densiflorum is the hardiest Hedychium by some distance.

Although the species is highly variable in the wild most that are in UK cultivation are from high elevations and are just as hardy as other plants from similar locations. They survived minus 17C here (also in Devon) without damage this last winter where we have them planted outdoors without additional protection.

That hardiness is interesting to know Ilex. Thanks.