Considering a role for native plant cultivars in ecological landscaping: an experiment evaluating insect preferences and nectar forage values of Phlox species vs. its cultivars
Nevison, Keith A.
University of Delaware
In the face of rapidly declining pollinator populations and a growing awareness of biological diversity lost through habitat destruction, many citizens are opting to transform their home landscapes into native plant havens to support wildlife. When gardeners visit nurseries to purchase native plants, however, they often encounter numerous cultivars, which may or may not provide equivalent ecological benefits to insects and other wildlife. To address this issue, in 2015 research was conducted in the Mt. Cuba Center Trial Garden in Hockessin, Delaware, USA that compared insect attraction, nectar quality and floral characteristics between U.S. Eastern Phlox species and associated cultivars. In total, 6 straight species, 2 subspecies and 15 cultivars were sampled to evaluate the factors having the greatest influence on insect visitation. ☐ The results from this experiment suggest that certain Phlox cultivars, especially those selected from the wild, are more attractive to insects than their straight species counterparts. For the majority of Phlox cultivars, however, insect attraction and nectar quality did not differ significantly in comparison to their associated straight species. In the case of Phlox paniculata and its cultivars, the narrowness of a flower’s corolla, in particular, has a strong influence on insect attraction. These results lend support to the notion that specific cultivars can serve an important role in ecological landscaping by providing vital habitat to insects and other wildlife. ☐ This study was among the first to test attraction between multiple cultivars and straight species for a specific genus. With myriad untested plants, there are significant opportunities for advancement of this type of research moving forward. Ultimately, additional experiments are recommended to better assess the individual characteristics governing insect preference in native plant cultivars.