P&PDL Picture of the Week for
September 17, 2007

More Fascinating Fasciation!

B. Rosie Lerner, Purdue Extension Consumer Horticulturist, Department of Horticulture & Landscape Architecture, Purdue University

Every so often gardeners find a deformed looking flower or stem that appears as if the plant has been hit with a growth regulator herbicide, yet only randomly affects a stem or two.  The stem or flower stalk will appear somewhat squashed and splayed, sometimes splitting in two or more sections. Or it may appear that two or more stalks have merged together to form one distorted structure.

This odd growth is called fasciation which literally translates to banding or bundling. Fasciation is thought to be caused by a hormonal imbalance that in some cases could be a random mutation. Some plants may be genetically predisposed to fasciation, most notably, the cockscomb Celosia. But in cases of random appearance, fasciation is induced by one or more factors including bacteria, fungi, virus, insects, frost, and physical damage to the growing point.

The good news is that fasciation itself is not “contagious” and does not spread through a planting.  And just because a particular plant exhibited fasciation one season, does not necessarily mean it will again in the future.  In most cases, fasciation is just a random oddity.  

Verbena photo courtesy of Rosie Lerner

Sweet potato photos courtesy of John Knipp, Jay County Agriculture Educator

Click image to enlarge

Fasciated verbena

Fasciated flower spike of Verbena hastata

Fasciated sweet potato

Fasciated sweet potato stems

Fasciated sweet potato

Fasciated sweet potato stems

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service