Landscape - Abnormal Branch: Injury or Chimera?

A chimera is a genetic mutation that leads to a different appearance in part of a plant. This is often confused with some kind of damage or injury. Many of our variegated plants were originally found as chimeras from a branch or shoot of a non-variegated plant. The following is a short article on the subject.

Chimeras are botanical abnormalities that are often confused with nutritional or chemical disorders. “Chimera” is a term used to describe a single plant with two genetically different tissue types. Leaf variegation is the most common example of chimeras in plant species. The difference in foliage color and the banding of those colors are due to cell mutations in the meristematic tissue layers. Chimeras can be stable, in that the genetic differences are consistent and reproducible. These chimeras have spawned numerous of our variegated plant cultivars. Chimeras can also be unstable and unpredictable, surfacing sporadically on either shoots or individual leaves. The Bumald spireas are known for the sporadic appearance of unstable leaf chimeras. The stability of the chimera depends on the tissue layer where the mutation occurs. If you discover variegation on an individual stem and not over the entire plant, it is possible that it is a chimera and not an abiotic disorder related to plant nutrition or chemical injury.

Chimera on Anthony Waterer spirea.

Information and photo from a section of "Abiotic Plant Disorders - Symptoms, Signs and Solutions A Diagnostic Guide to Problem Solving" by Robert E. Schutzki and Bert Cregg, Departments of Horticulture and Forestry, Michigan State University Michigan State University. Go to http://www.ipm.msu.edu/cat08land/pdf/9-19abiotic.pdf for the full factsheet with photos.