Kenneth D. Cochran, Secrest Arboretum of The Ohio State University Ohio Agricultural Research and Development Center, Wooster, Ohio; and James A. Chatfield, Ohio State University Extension, Northeast District and Department of Horticulture and Crop Science.
For practical purposes, evergreens are defined as coniferous (cone bearing) or broadleaved; examples of the former are hemlock, arborvitae, juniper, and pine and examples of the latter are rhododendron, azalea, and holly. Not all hollies are broadleaved evergreens, however; some are leafless in the dormant winter and are collectively called deciduous hollies.
To the average reader, "holly" conjures up a picture of a shiny-leaved plant with bright red fruit. However, holly enthusiasts know that these spiny-shiny hollies are not the only taxa in the nearly 700 species of the genus Ilex, family Aquifoliaceae. Plants in the holly family are dioecious; male and female flowers are on separate plants.
Most hollies are a welcome sight in the winter landscape or as sprigs of "specialty cuts" for interior decoration. Whether it is the luxuriance of their evergreen foliage against contrasting colored fruit, the potential for placing potted specimens on a cool solarium, or the brightly colored fruit on leafless branches of the deciduous holly, Ilex helps brighten the winter months.
Hollies to plant in USDA Cold Hardiness Zone 5b at Secrest Arboretum include: Ilex opaca, American holly; Ilex crenata, Japanese holly; Ilex pedunculosa, longstalk holly; Ilex verticillata, Michigan winterberry; Ilex x meserveae, Meserve holly; Ilex glabra, inkberry holly and Ilex serrata, Japanese winterberry.