White Peonies bloom in the late spring and early summer. Depending upon your hardiness zone, peonies may begin blooming in April, May or June. Peony plants might have a short season, but their beauty and fragrance make planting them well worth it. Peonies are typically planted in springtime, so that they'll enjoy a nice year of blooming before the frost hits. Most peonies are hardy in Zones through 8.