Companion planting with peonies (Paeonia spp.) is an art that enhances the garden's beauty, health, and productivity. From a botanical perspective, the ideal companions are those that share similar cultural needs without competing aggressively for resources. Peonies thrive in well-drained soil and full sun, requiring a winter chill period for dormancy. Their companions should therefore be sun-loving, not overly thirsty, and have non-invasive root systems that respect the peony's substantial tuberous roots.
Peonies have a relatively short but spectacular bloom period in late spring to early summer. To maintain visual interest, pair them with plants that bloom before or after. Spring-flowering bulbs like Alliums (ornamental onions) are perfect. Their spherical blooms rise above the peony's emerging foliage, and once the bulbs fade, the peony's large leaves help disguise their dying foliage. Later, the peony's lush, shrub-like form provides a magnificent green backdrop for summer-blooming perennials like Phlox and Lilies, which take over the floral display just as the last peony petals fall.
The peony plant is valued for its large, often deeply lobed, dark green leaves that form a substantial mound. Companions with contrasting foliage textures and forms create a more dynamic and visually appealing border. The fine, airy texture of ornamental grasses like Blue Fescue (Festuca glauca) or the spiky, architectural form of Irises provides a stunning textural counterpoint. The bold, broad leaves of Lady’s Mantle (Alchemilla mollis) also complement peony foliage beautifully, and its frothy chartreuse flowers spill gracefully around the peony's base.
While peonies are largely pest-resistant, they can be susceptible to botrytis blight in humid conditions. Companion plants that improve air circulation around the peony's base are crucial. Low-growing, mounding plants like Catmint (Nepeta) or hardy Geraniums (Cranesbill) are excellent choices. They cover the bare "legs" of taller peonies, suppress weed growth, and their open habit allows for good airflow. Furthermore, the strong scent of herbs like Lavender is believed by many gardeners to help deter pests like aphids that might bother other plants in the vicinity.
This is a critical consideration from the plant's perspective. Peonies develop deep, tuberous roots that resent disturbance. They should not be planted with aggressive, spreading plants that might compete for water and nutrients or require frequent digging that could damage their roots. Avoid companions like mints or gooseneck loosestrife. Instead, choose plants with shallow or non-running root systems. Coral Bells (Heuchera), with their shallow roots and colorful foliage, are ideal, as are many annuals like Nicotiana or Cleome, which can be planted without disturbing the peony's root zone.
