There is increased interest in using native shrubs for landscaping to support pollinators (Gagliardi and Brand, 2007; Tallamy, 2007). Nurseries producing landscape plants typically grow cultivars, which are selections with better performance and ornamental characteristics than is typical of straight species (Wilde et al., 2015). Native shrubs produced from seeds are less marketable to a broad base of consumers because of variable quality (Getz, 2015). Straight species of native shrubs are frequently less suitable for landscaping because many are naturally large in stature and consumers desire native shrubs that will fit their landscape and also support pollinators (Hansen, 2017). For this reason, nursery growers prefer to produce cultivars of native shrubs that maintain a compact habit. Native shrub cultivars have also been selected for having unique flower or foliage coloration or form compared with the straight species.
Some consumer and conservation groups claim that native plant cultivars (nativars) are less frequently visited by pollinators than the straight species and are, thus, less useful for developing pollinator plantings (Hansen, 2017). A limited number of studies have compared pollinator visitation for native herbaceous perennials and their cultivars. White (2016) evaluated insect visitation for 11 different native herbaceous perennial species and a single cultivar of each species. Similarly, Poythress and Affolter (2018) evaluated three native herbaceous perennial species and one native grass species and a single cultivar of each species. Nevison (2016) compared insect visitation for native Phlox paniculata and six of its cultivars. We could locate no published scientific studies comparing pollinator visitation for native shrub species and their cultivars. Baisden et al. (2018) evaluated caterpillar feeding damage for 10 native woody plant species and 18 cultivars selected for six different desirable traits. We evaluated insect pollinator visitation for six native shrub species and one or more cultivars of each species, which were selected for traits, including compact habit, foliage color, flower color, or flower form. The objectives of this research were to determine if cultivars attracted the same number of insects as their species and to observe the diversity and quantity of different groups of insects.
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