We grow them with Dahlias and between climbing Roses.
Jim

Gypsophila paniculata.

swath of siberian iris makes an effective foliage foil/fence.
best,
mindy

Gypsophila paniculata is a Class C noxious weed in WA state, so not a well advised suggestion. Most nurseries have stopped selling it and I can't think of any of the common perennial wholesalers that even offer it any longer.

Once the poppies have finished blooming, both the bloom stalks AND the foliage can be cut back to ground level. A fresh rosette of foliage will resprout and that will maintain a decent appearance for the remainder of the season. Simply cutting back and interplanting with your choice of other, later blooming perennials or small shrubs will provide a tidier look. Or fill in with fast growing annuals.