The desire to attract butterflies is a common goal for many gardeners. The garden plants widely known as “geraniums” are popular annuals, celebrated for their bright colors and continuous summer bloom. This popularity leads to a frequent question about their effectiveness as a pollinator source. To understand the relationship between these common flowers and winged visitors, it is necessary to clarify a point of botanical confusion and examine the specific biological needs of butterflies. This information clarifies why the typical garden “geranium” is not a significant butterfly magnet and suggests effective alternatives.
The Direct Answer: Geraniums Versus Pelargoniums
The plant most people refer to as a geranium is botanically classified as a Pelargonium, a distinction that holds the key to its limited attraction for butterflies. True Geraniums, often called cranesbills or hardy geraniums, are perennials with radially symmetrical flowers that occasionally attract smaller butterfly species. In contrast, Pelargoniums are asymmetrical and are widely cultivated as annuals for their vibrant, often clustered blooms.
The primary reason Pelargoniums are poor butterfly food sources is their low nectar production. The flowers have often been bred for maximum visual appeal rather than for pollinator reward, meaning they offer little energy to a foraging insect. Many popular varieties also feature double or complex flower structures, which physically block a butterfly’s long, thin proboscis from reaching any available nectar.
Furthermore, the foliage of many Pelargonium varieties releases a strong, often pungent, scent. While some insects are attracted to potent odors, butterflies generally rely on visual cues and prefer mild or sweet floral scents for foraging, making the strong aroma potentially repellant. While Pelargoniums are not a good nectar source, some species are known to serve as host plants for the larvae of the Geranium Bronze butterfly, a specific relationship that does not involve adult feeding.
Understanding Butterfly Flower Preferences
Butterflies have specific sensory and physical requirements for a flower to be considered a viable food source, largely prioritizing visual cues over scent. They possess good vision and can perceive a wide range of colors, including red, which is often invisible to bees. As a result, flowers in shades of pink, purple, yellow, and red are generally the most attractive to foraging butterflies.
The physical architecture of the flower is equally important, as butterflies are relatively large insects that require a stable place to land while feeding. They preferentially visit flowers that are clustered or possess flat, broad petals that function as a suitable landing platform. This preference explains why deep, tubular flowers or tightly closed double blooms are often ignored.
Nectar quality and accessibility are the final determining factors for a successful visit. Butterflies use their proboscis to access liquid energy. They seek flowers that produce abundant nectar accessible by their specialized feeding apparatus. The combination of bright color, a stable landing area, and a rich, accessible nectar supply drives their foraging decisions.
Effective Plants to Attract Butterflies
Gardeners seeking to create a successful butterfly habitat must provide flowers that meet these specific biological needs, serving both the adult butterflies and their young. Effective planting involves providing two distinct types of plants: nectar sources for adult energy and host plants for larval development. Nectar-rich annuals and perennials offer the high-energy fuel that adult butterflies require for flight and reproduction.
Excellent nectar sources include:
- Purple Coneflower (Echinacea) and Zinnia, which feature flat, composite flower heads that offer a landing pad and abundant nectar.
- Butterfly Bush (Buddleia) and Lavender, which produce dense clusters of small, nectar-laden flowers that are easily probed.
- Late-season bloomers such as Asters, which provide energy for fall migratory species like the Monarch butterfly.
To support the butterfly lifecycle, host plants must be introduced, as the larvae feed only on specific foliage. The most well-known example is Milkweed (Asclepias), which is the sole host plant for the Monarch caterpillar. Similarly, herbs in the carrot family, such as dill and parsley, serve as food for the Black Swallowtail caterpillar.