Answer: Most perennials bloom for only a short time, so you may also want to consider white flowered annuals such as cosmos, snapdragons, and begonias. Among perennials, you could consider Clematis, roses, Iris, daisies and mums, Dianthus, Platycoden, Heuchera, candytuft, Phlox paniculata "David", and Japanese anemones. You might also look for white flowered forms of Baptisia, cranesbill, Hemerocallis, and Coreopsis. I hope this gives you some ideas.
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