Best peony cultivars: herbaceous, tree, and intersectional

The first peony I planted, in 2009, was a pale pink herbaceous cultivar from a big-box garden center -- no label beyond "peony." It bloomed the following May in three-inch flowers that nodded to the ground in the first rain. I staked it, which helped, and it has since grown into a tight clump that.

The first peony I planted, in 2009, was a pale pink herbaceous cultivar from a big-box garden center — no label beyond "peony." It bloomed the following May in three-inch flowers that nodded to the ground in the first rain. I staked it, which helped, and it has since grown into a tight clump that puts up 18—20 stems a year. I've added tree peonies and intersectionals since then and have grown five cultivars in my zone 7a Long Island garden.

Peonies as a group are long-lived, slow to establish, and intolerant of incorrect planting depth. The most common reason a peony fails to bloom is that it was planted too deep. That single problem accounts for more frustrated gardeners than any pest or disease.

Types of peonies: what you're actually buying

Per Missouri Botanical Garden:

• Herbaceous peonies (Paeonia lactiflora and hybrids): die to the ground each fall, regrow from fleshy roots each spring. The most widely available type.
• Tree peonies (Paeonia suffruticosa and related species): woody shrubs that retain their stems year-round. Flowers are 6—12 inches across. Slower to establish.
• Intersectional (Itoh) peonies (Paeonia × itoh): hybrids between herbaceous and tree peonies. The stems die back partway in fall. Larger flowers than herbaceous, better heat tolerance than tree peonies, excellent disease resistance.