Gardeners grow plants for many reasons, including food production and the beauty of the plants and their flowers. Some also grow plants with the specific intent of attracting butterflies and providing food for their caterpillars, a practice called "butterfly gardening." Zinnias are recommended frequently for inclusion in butterfly gardens as nectar sources for adult butterflies, but little has been known about butterfly preferences for different zinnia cultivars.
Dr. Ken Yeargan and Sarah Colvin, graduate research assistant, recently compared four commonly available zinnia cultivars with regard to their attractiveness to butterflies. Mixed-color plantings in replicated plots were used for all cultivars in a field study. Butterflies were counted in the morning and in the afternoon once per week over a seven-week period.
Based on a total count of 2,355 butterflies, representing 30 species, more than twice as many total butterflies visited 'Lilliput' than visited any of the other cultivars. Also, more species of butterflies (27 species) visited 'Lilliput' than any other cultivar (17 to 22 species).
'Lilliput' is an heirloom zinnia cultivar that dates from the 1870's. Fortunately its seeds are readily available from local stores and internet vendors. While most zinnia cultivars will attract butterflies, these results indicate that 'Lilliput' would be an excellent cultivar choice for use in butterfly gardens.
These findings were published in the March 2009 issue of the Journal of Environmental Horticulture. Click here for a PDF reprint of the journal article. Katie Pratt also covered the story on the University of Kentucky agNews site. Read the full article here.