Where should you plant autumn gentians? Neutral to acid soil is essential; Gentiana sino-ornata and its hybrids loathe lime, so if your soil is alkaline, plant them in pots with ericaceous compost. Drainage and moisture: autumn-flowering gentians enjoy free-draining, moist soil because their natural habitat is the damp mountain meadows and open forest and scrub of the Himalayas, where the annual snow melt runs around their roots.