Peony

A peony is a plant you plant once and inherit to the next generation. A well-sited peony can live for fifty years, a hundred years, longer — there are documented specimens that were planted before the Civil War and still bloom every spring. But the contract between gardener and plant is signed at planting, and the single most common way to break it is to plant the eyes too deep.

The eyes are the dormant buds at the crown of the root, and they need to sit one to two inches below the soil surface — no more. A peony planted three or four inches deep may grow lush green foliage for years, even decades, and never produce a single flower. The plant is alive, the plant is healthy, but the eyes are too far from the light to trigger bloom. Digging it up and replanting at the correct depth usually fixes the problem, but it means losing another two or three years while the plant re-establishes.

When you plant, dig a wide hole — eighteen inches across, a foot deep — and amend the soil with compost or aged manure. Set the root so the eyes are pointing up and measure the depth carefully before backfilling. In warmer climates — zones 7 and 8 — plant the eyes even shallower, at one inch or less, because the soil stays warmer longer in fall and the plant needs less insulation.

Peonies bloom in late spring, usually May, and the flowers are large, heavy, and prone to flopping in rain. Staking or a peony ring installed early in the season keeps the stems upright. The ants that crawl over the buds in the weeks before bloom are there for the nectar — they do no harm to the plant and need no intervention. Botrytis blight, a fungal disease that causes buds to blacken and fail to open, is the real threat in wet springs. Remove affected buds immediately and cut all foliage to the ground in fall to reduce overwintering spores.

Peonies are slow to establish and resent being moved. A newly planted peony may take two or three years to bloom, and the first year's blooms are often sparse. This is normal. The plant is building a root system that will support decades of flowering. Once established, a peony requires almost no care — an annual topdressing of compost in early spring, removal of spent flowers to prevent seed formation, and a hard cut-back after the first hard frost in fall.

In the South, where winters are mild, peonies struggle. They need a period of cold dormancy — at least 500 chilling hours below 45 degrees — to set buds for the following spring. Gardeners in zones 8b and warmer may find that peonies grow foliage but bloom poorly or not at all.