The lush, abundant blooms of peonies (genus Paeonia) are a classic sight in the late spring garden, often inspiring gardeners with their beauty and fragrance. Many people look for ways to integrate these flowers with pollinator-friendly practices, envisioning butterflies fluttering among the massive blooms. However, the reality is that the relationship between these two garden staples is largely non-existent. The specific biology and structure of most peonies make them a poor food source for butterflies.
The Peony Problem: Why Butterflies Avoid Them
The primary reason butterflies pass over peonies is the structure of the flower itself. Most popular peony varieties feature a dense, multi-layered bloom that physically obstructs access to the reproductive organs. A butterfly feeds using a long, straw-like mouthpart called a proboscis, which it uncoils to reach nectar deep within a flower.
The tightly packed petals of a peony create a barrier that prevents the butterfly from reaching the nectaries at the flower’s base. Furthermore, the sheer weight and complexity of the bloom do not offer the flat, stable surface that a butterfly requires for a secure landing platform. Butterflies often need to land and stand still to feed, which is difficult on the rounded, heavy peony flower.
Peonies also do not offer a substantial reward for the effort a butterfly would expend trying to navigate the bloom. Many hybridized varieties have been bred for showiness, leading to a reduction in the production of accessible nectar and pollen. The energy reward is simply too low to attract a butterfly, whose entire adult life is dedicated to fueling flight and reproduction.
Single Blooms Versus Double Blooms
The peony’s effectiveness as a pollinator plant depends heavily on its bloom form. Peonies are categorized into several forms, but the most significant difference for pollinators is between single and double blooms. The typical garden peony is a double-bloom variety, where the stamens have been converted into extra petals.
This process, known as “petaloid transformation,” eliminates the flower’s reproductive center, leaving no pollen or nectar. Double peonies, often having a “bomb” or full-double shape, are purely ornamental and offer no biological reward. Conversely, single-bloom peonies feature one or two rows of petals surrounding a visible center of stamens and carpels.
These single and semi-double varieties offer a slight advantage because their exposed centers provide easier access to limited nectar and pollen. While they are a better option for general pollinators like bees, they are still not a preferred food source for butterflies. Single varieties, such as ‘Krinkled White’ or ‘Blaze,’ remain a secondary choice compared to other nectar plants.
What Butterflies Need in a Flower
Butterflies have specific biological requirements that dictate which flowers they prefer for feeding. They require a steady supply of high-sugar nectar to fuel their metabolism and sustained flight. The ideal flower must have a substantial nectar reward, containing a sugar concentration between 20 and 25 percent, which is easily accessible.
Flower shape is another crucial factor, as butterflies prefer an open, flat surface that serves as a secure landing platform. This allows them to land and feed without struggling to maintain their footing. Tubular flowers that are clustered together, such as those in the aster family, also work well, allowing the butterfly to perch on the cluster while reaching the nectar.
Butterflies are drawn to brightly colored flowers, particularly those in the red, orange, pink, and purple spectrums. They possess excellent color vision, including the ability to see ultraviolet light. This reveals patterns on petals called “nectar guides” that lead the butterfly directly to the nectar source, ensuring efficient energy collection.
Optimal Butterfly Garden Plants
Gardeners aiming to attract butterflies should focus on plants that meet their specific needs for landing and high-quality nectar. Plants that feature flat, clustered flower heads and a continuous bloom period are the most effective nectar sources.
Highly effective nectar producers include:
- Purple Coneflower (Echinacea purpurea), which provides excellent landing pads.
- Blazing Star (Liatris), offering accessible nectar.
- Zinnias (Zinnia elegans), which bloom profusely.
- Joe-Pye Weed (Eutrochium), providing a vital energy source in late summer.
- Asters (Symphyotrichum), which are crucial for migrating species.
Beyond nectar, a successful butterfly garden must also include host plants. These are the specific species that female butterflies lay their eggs on and that the emerging caterpillars feed upon. Monarch butterflies, for instance, are entirely dependent on Milkweed (Asclepias) as their host plant.