Dealing with freeze injury to ornamental plants

Jean Williams-Woodward, Extension Plant Pathologist

Freeze injury symptoms can include blackening or bleaching of foliage, tip dieback, stem or branch splitting, and plant death. The damage may not be readily apparent, especially on trees. Trunk damage and splitting may develop months to years later.

Often weak pathogens invade the damaged tissues resulting in trunk and branch cankers (usually from Botryosphaeria spp. infection) and secondary infection by weak pathogens, such as Colletotrichum spp. and Pestalotiopsis spp.

The best approach to deal with freeze injured tissues is to prune off the affected tissues. Prune dead branch tips after bud break. Give plants, such as liriope, a shearing to remove dead foliage.

Freeze on boxwood Woodward

Freeze on cast iron plant Woodward

 

 

 

 

 

 

 

 

 

 

Freeze injury symptoms of bleached, necrotic foliage and split bark (seen at arrows) on boxwood (left), cast-iron plant (upper right) and holly (bottom right). (Images of holly and cast-iron plant by Jean Williams-Woodward; Image of boxwood by Greg Bowman, Gordon County Extension Coordinator)

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