Itoh Peony Flowers

Many peonies can be grown with little to no problems with disease, especially when planted in the correct location. But a new class of peonies—a cross between tree peonies and garden peonies (Paeonia suffruticosa x Paeonia lactiflora)—have superior disease resistance. In spring, the plant re-grows long, woody stems. "At the end of May, large buds open to a bright yellow mass of petals," says Adrienne Roethling.