How to Prune plantain lily 'Rainforest Sunrise'?
No pruning required

plantain lily 'Rainforest Sunrise' · Hosta 'Rainforest Sunrise'
Grow in fertile soil that does not dry out, in a shady spot away from direct sun; leaf colour will be greener in deeper shade. Provide shelter from cold, drying winds, and mulch annually in spring. Hostas in the ground may need watering during dry spells. See hosta cultivation for more detailed advice
No pruning required