Pansies, which belong to the Viola genus, have a complex and often misunderstood relationship with butterflies. The answer to whether a butterfly “likes” a pansy depends entirely on what the insect needs at that moment in its life cycle.
The adult butterfly seeking immediate energy from nectar generally finds pansies to be a poor food source compared to many other garden flowers. Conversely, certain butterfly species rely exclusively on pansies and their relatives for the survival of their offspring. This difference means the pansy functions not as a butterfly cafeteria, but as a nursery for the next generation.
Pansies as a Nectar Source
Adult butterflies require regular intake of nectar, a sugar-rich liquid that fuels their flight and reproductive activities. They typically seek flowers that offer a high concentration and volume of this fuel reward. Pansies, with their relatively open and shallow floral structure, do not usually meet this high-energy demand.
Many preferred butterfly flowers are tubular or clustered, a morphology that protects the nectar deep inside the corolla. This structure forces the butterfly to uncoil its long proboscis, ensuring that the flower’s pollen is effectively transferred during the visit. Pansies lack this deep, tubular form, making their nectar readily accessible but often low in quantity.
Flowers that are clustered or flat-topped, such as those in the Aster family, provide a stable landing platform and allow the butterfly to sip from multiple miniature florets without expending energy on repositioning. The single, open shape of the pansy offers a platform but generally limits the insect to a single, small nectar source per flower head.
Research suggests some field pansy populations are evolving toward smaller flowers and reduced nectar production. This indicates the plants are increasingly relying on self-pollination rather than attracting external pollinators, thus reducing their appeal to nectaring butterflies. Butterflies are opportunistic, preferring high-yield sources like Zinnias or Milkweed, and will often bypass a pansy for a more rewarding bloom.
Pansies as a Host Plant
While adult butterflies may overlook pansies for nectar, the plant serves a more important biological function as a host plant. A host plant is a specific species on which a female butterfly lays eggs, providing the sole food source for the developing caterpillar larvae.
The most notable species with this relationship are the Fritillary butterflies, including the Variegated Fritillary and the Great Spangled Fritillary. These species have specialized to use plants in the Viola family, which includes pansies and wild violets, as the exclusive food for their young.
A female Fritillary butterfly actively searches for pansies or violets to deposit her eggs, ensuring her offspring have the necessary chemical compounds for growth and survival. The resulting caterpillars, sometimes called “pansyworms,” consume the leaves, flowers, and even the stems of the plant.
This specialized larval diet is a bottleneck in the butterfly life cycle; without the host plant, the species cannot reproduce. Therefore, the Fritillary’s presence relies directly on the availability of pansies or violets in the landscape. Planting pansies is a direct contribution to supporting the complete life cycle of these specific butterfly species.
Enhancing Your Garden for Butterflies
To support a healthy and diverse butterfly population, a garden should provide both host plants for larvae and rich nectar sources for adults. Integrating pansies fulfills the host plant requirement for Fritillaries, but they should be strategically placed alongside high-nectar blooms.
Consider planting high-yield nectar flowers, such as Zinnias, Cosmos, or Asters, to provide the necessary energy for adult butterflies. These plants offer the clustered shapes and substantial nectar content that flying insects prefer for efficient feeding.
It is beneficial to plant pansies in a slightly out-of-the-way location, as the leaves will be consumed by the caterpillars. Providing a sunny area with flat stones or bare soil also offers a location for butterflies to bask and warm their flight muscles. Finally, eliminating the use of broad-spectrum pesticides is important, as these chemicals will indiscriminately kill the beneficial caterpillars feeding on the pansies and other host plants.