Zinnias (Zinnia elegans) are popular annual flowers that provide vibrant color all summer long. They attract a wide array of insects and birds, but their benefit to the ecosystem depends entirely on the specific variety chosen. When selected correctly, zinnias provide an abundant, high-quality source of both nectar and pollen, sustaining pollinator populations from mid-summer until the first frost.
The Essential Zinnia Feature: Flower Structure
A zinnia’s ability to feed pollinators is determined by its flower structure, which is a composite head composed of two flower types. The showy, colorful parts recognized as petals are the outer ray flowers. The tiny, often yellow or orange, structures clustered in the center are the disk florets, which contain the reproductive parts that produce accessible nectar and pollen.
The critical distinction for any pollinator garden is between single-petal and double-petal varieties. Single-petal zinnias feature a prominent, open center where the disk florets are completely exposed to visiting insects. Conversely, double-petal zinnias, often bred for a dense, pom-pom appearance, have an increased number of ray petals that fully obscure the central disk florets. This physical barrier prevents most pollinators from reaching the necessary resources, making these varieties largely ornamental and non-functional as a food source.
Who Visits Zinnias?
When single-flowered varieties are planted, zinnias become a busy hub for several major pollinator groups. The bright, flat-topped blooms are especially attractive to butterflies, which use the flower head as a stable landing platform. Butterflies, such as Monarchs, Swallowtails, and Painted Ladies, use their long proboscis to easily access the nectar in the exposed disk florets. They are also sensitive to the vibrant red, orange, and pink colors prevalent in many zinnia cultivars.
Bees, including honeybees, bumblebees, and native species, are frequent visitors seeking both pollen and nectar to fuel their colonies. They are attracted to the clear visibility of the central pollen source and work the disk florets to gather the protein-rich grains. While bees do not see red well, they are strongly drawn to the yellow, purple, and blue hues offered by certain zinnia types. The open structure of the single flower allows for quick and efficient resource collection.
Hummingbirds, though less common than insects, use zinnias for their high nectar content. These birds are particularly attracted to flowers with red or scarlet coloration, often favoring varieties with slightly more tubular shapes. Cultivars like the Profusion series, known for their abundant, open blooms, are popular with hummingbirds. Zinnias provide a reliable, long-lasting food source throughout the late summer and fall when other flowers have finished blooming.
Cultivation Choices for Pollinator Support
Gardeners maximize the ecological benefit of zinnias by making informed choices about planting and maintenance. The first step involves selecting specific single-flowered or heirloom varieties, which retain the exposed disk florets necessary for pollinator access. Varieties such as ‘Cut and Come Again,’ ‘State Fair,’ and the ‘Zahara’ series are excellent choices for their open centers and prolific blooming habits. Focusing on these types ensures the plants provide a tangible food source rather than just visual appeal.
To increase visibility and attract pollinators from a distance, zinnias should be planted in large groups or drifts. A mass of color acts as a more powerful beacon than scattered individual plants, guiding bees and butterflies to the food source more effectively. Locate these plantings in a spot that receives full sun for at least six hours a day, as this promotes the most vigorous growth and flower production.
A simple yet effective action is the practice of deadheading, which involves removing the spent or faded flowers from the plant. This process prevents the plant from expending energy on seed production, instead directing that energy back into creating new blooms. Consistent deadheading throughout the season ensures a continuous supply of fresh nectar and pollen, maintaining the zinnia patch as a reliable food source until the first hard frost.