Most woody plants are not susceptible to black root rot disease and could be used as replacements for declining holly plants. The few exceptions include catalpa, elm, holly, lilac, and possibly boxwood and taxus.
Holly susceptibility varies with the species. Black root rot is most frequently observed on Japanese holly, blue holly, and inkberry in Kentucky. Susceptible blue holly cultivars include: Blue Angel, Blue Maid, Blue Prince, Blue Princess, Blue Stallion, China Boy, China Girl, and Dragon Lady. While English and Chinese hollies are reportedly resistant, American and Yaupon hollies are considered to be only moderately resistant. Other ornamentals known to be susceptible include begonia, cyclamen, geranium, gloxinia, oxalis, petunia, phlox, poinsettia, sweet pea, verbena, and viola. English boxwood was also found to be susceptible in greenhouse inoculation studies.
