Issue 7, June 5, 2012
Reversion is a term used to describe when a cultivar, known for a particular leaf shape, color, or other characteristic, 'reverts' back to a different form found in the plant's parentage. The term is often used to describe a variegated shrub or tree that produces non-variegated shoots.
Variegated European beech (Fagus sylvatica 'Purpurea Tricolor') with branch reverting back to purple leaved form.
Many of the unique cultivars we use in our landscapes originated from sports or mutations growing on plants with normal or true species characteristics. Sports may differ by foliage shape, color, and branch structure. Breeders and growers propagate the more interesting sports and introduce them into the trade. These mutations, however, are not always stable and may revert back to the parent plant form, e.g. all green leaved form.
Picea glauca 'Alberta Blue' reversion. Blue needles are typical of the Alberta Blue cultivar. Green needles are a reversion to the parent form. Photo taken by Dr. Gary Kling.
The reverted portion of the plant will generally be more vigorous than the rest of the plant. If allowed to remain on the plant, reversions may eventually outgrow and overtake the desirable cultivar. Your best course of action is to prune out the reverted portion of the plant. Prune back to a portion of the plant displaying normal characteristics of the cultivar. (Travis Cleveland)