How to Prune Papaver 'Shasta'?
Cut spent flowering stems back to the ground, cut back foliage as it fades

Papaver 'Shasta' · Papaver 'Shasta'
Will thrive in most soils, as long as there is good drainage, but a moderately fertile, humus-rich soil that is not too acidic is ideal. Position in full sun and provide support, as stems can flop after heavy rain (see staking: perennials)
Cut spent flowering stems back to the ground, cut back foliage as it fades