Ornamental grasses referred to as fountaingrass or napiergrass, collectively referred to as pennisetums, belong to the genus Pennisetum (Poaceae), which is a genus of ≈80 species native to tropical, subtropical, and warm temperate regions (Huxley and Griffiths, 1992). The genus is known for drought tolerance, and the variety of species presents opportunities for novel ornamentals. For instance, napiergrass (P. purpureum) has been selected for its ornamental purple foliage and includes selections such as ‘Prince’ and ‘Princess’ (Hanna and Ruter, 2005). Breeding at the University of Georgia led to hybrids that included complex interspecific, interploid crosses. Hanna et al. (2010) released ‘Tift 17’ and ‘Tift 23’ that included pearl millet [P. glaucum (2n = 4x = 28)], napiergrass (2n = 4x = 28), and a wild relative of pearl millet [P. squamulatum (2n = 8x = 56)] in their pedigrees. Ongoing breeding and selection has developed selections with deep purple foliage color, varied textures, disease resistance, and apparent sterility (seed and pollen). Recent selections, including those tested in the current research, were bred using germplasm with cytoplasmic male sterility, were selected to flower under short days (<10.5 h), and were the result of complex pedigrees; all of which contribute to their seedlessness. Furthermore, their roots are fibrous and the plant expands by producing tillers. This is in contrast to rhizomatous species that have the potential to spread vegetatively. The purpose of this research was to evaluate seven complex hybrid pennisetums developed at the University of Georgia for their potential as nursery and landscape plants for the Pacific northwestern region of the United States.
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