Choosing Colors in the Garden to Attract Pollinators
Bumble bee on the bright pink blooms of rose (or swamp) milkweed (Asclepias incarnata). Mandy L. Smith, Penn State
Color is a very important factor in garden design. Using color well is both a skill and an art. Color choice is often driven by personal preferences, including the feelings that colors can evoke. Red is a hot, strong color. Blue is a warm, soothing color. White can add a luminous, bright quality to a shade garden, and can even make the area seem closer. Dark colors make the shade garden recede. Conventionally, a gardener may choose flowers with colors that fulfill a defined need in their garden design, but color may also be used to draw in pollinators purposefully. Selecting colors specifically to entice pollinators to your garden need not adversely impact your garden design. There are many plants to choose from whose colors will work within your existing design. Generally, pollinators prefer brightly colored flowers. Yet, the color of a flower is not its only attractive characteristic. The flower's shape, form, floral phenology (timing), depth of the corolla (collective ring of all of the petals), amount of pollen and nectar, quantity of blooms, and sometimes scent, also play a role in bringing pollinators to plants. Please refer to the resources at the bottom of this article for lists of native flowering plants for different types of pollinators.
Bees
Bees see the world differently from humans. They see colors more quickly. Bees use their vision to find appropriate flowers. Their compound eyes have three color receptors. Humans see color combinations of red, blue, and green. Bees see color in combinations of blue, green, and ultraviolet (UV). They cannot see red, but they can see yellow and orange. Importantly, their sight includes the ultraviolet spectrum, which means that they see iridescence, which is the quality of flower petals changing color depending on the angle of view. Many flowers have evolved with structures that are visible in the UV range.
The flowers that bees are attracted to often appear violet/purple/blue, yellow, or white, or have petals that contain UV patterns. Please note that bees tend to prefer disk-shaped flowers that have easily accessible nectar. Some small and long-tongued bees like tubular flowers.
Butterflies
Where humans only have three receptors for color (red, blue, and green), butterflies have from 6 to 15, depending on species. Indeed, butterflies have the broadest range of spectral vision of any insect or animal, from UV, violet, blue, green, through red. They clearly see the world differently. They also see it more intensely. While humans have two lenses, one in each eye, butterflies have two large compound eyes, each having about 12,000 lenses. The weakness of their eyesight is distance. They are near-sighted, seeing only up to 100 feet away. Their blurry vision means that a large stand of color, such as a large drift of the same plant, will be more easily identifiable to butterflies. They use their eyesight and their ability to perceive color differences to locate food sources. Butterflies are attracted to bright colors along the spectrum, such as red, orange, yellow, pink, and blue/purple. Please note that butterflies need to land in order to feed, so specific shapes are critical—either large, flat flowers or flowers that are small but densely clustered.
Flies
Though they seem to get little attention, flies are the second most important plant pollinator after bees. Flies see and process vision very quickly. That's why it's so hard to swat them.
A variety of flowering plants are found to be attractive to flies. Generally, they tend to prefer flowers that have open structures that are easy to access. Blooms of white, cream, yellow, and green are preferable. Flies are not as efficient at pollinating as bees, but they are prolific. Flies also use their sense of smell to find food, and can be found on flowers that are musty-smelling or smell like decomposing material.Â
Hummingbirds
Unlike flies, hummingbirds don't use their underdeveloped sense of smell to find food. They use their sense of color. They can see the entire color spectrum from ultraviolet through red, and also many combinations, like ultraviolet and red together. The colors of flowers preferred most by hummingbirds are bright red, pink, and orange. Yet, they can be found eating from flowers of most colors. They are omnivores, as they eat insects too. Please note that hummingbirds prefer flowers that are tubular-shaped, including natives such as columbine, trumpet honeysuckle, cardinal flower, and wild bergamot. Plant a large swath of the same plant to entice hummingbirds to your garden.
When designing your home garden, personal taste, family needs, and preferences each play a key role. Color is one critical component of design. Yet color is a complicated component in that it is ever-changing in the garden. Most perennials have a few short weeks when they provide colorful blooms. To provide for pollinators, the gardener must grow preferred flowers that come in the preferred colors and shapes that bloom throughout the timeframe when the pollinators are active. A succession of enticing blooms is the goal. The good news is that your use of color to meet your human design preference goals need not be mutually exclusive with meeting the goal of providing food for pollinators. You can find a plant along the color spectrum that would be preferred by a pollinator. Choosing what works for you and your home/landscape combination can also work for a variety of different pollinators, including hummingbirds, bees, flies, and butterflies.
