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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Publications at this Location » Publication #391642
Research Project: Blueberry and Woody Ornamental Plant Improvement in the Southeast United States

Location: Southern Horticultural Research Unit

Title: Impacts of shade treatments on dormancy of overwintering redbud (Cercis canadensis L.) trees at southeastern nurseries.

Author
item Werle, Christopher
item WITCHER, ANTHONY - Tennessee State University

Submitted to: Journal of Environmental Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2022
Publication Date: 7/19/2022
Citation: Werle, C.T., Witcher, A.L. 2022. Impacts of shade treatments on dormancy of overwintering redbud (Cercis canadensis L.) trees at southeastern nurseries.. Journal of Environmental Horticulture. 40:79-86.

Interpretive Summary: Dormancy accrual is an important step in mitigating the potential abiotic stressors of overwintering trees at ornamental nurseries, with frost-injured tree crops at heightened risk of ensuing biotic insect and disease attack. Using potted eastern redbud (Cercis canadensis L.) trees placed under two types of shade cloth, under full sun, or in walk-in coolers, we tested stem and root zone temperatures, accrual of chill hours and mean time to bud break. While there was no significant difference between the two shade treatments, shade cloths did moderate both high and low temperatures that trees were exposed to. In general, shaded trees did not have a significantly different mean time to first bud break from trees in full sun. It may be useful to alter the shading design to continue protecting from overnight lows, while preventing excess warming from daytime highs, and thus preventing frost exposure while not losing dormancy, but further tests will be required.

Technical Abstract: Winter dormancy is an important part of the natural process that trees use to protect against cold injury and other ensuing problems. Using potted eastern redbud (Cercis canadensis L.) trees placed under two types of shade cloth, under full sun, or in walk-in coolers, we looked for differences in stem and root zone temperatures, accrual of chill hours and mean time to bud break. Shaded trees did not differ in time to first bud break from trees in full sun, and there was not a temperature difference between the two shade treatments, but shade cloths did moderate both high and low temperatures that trees were exposed to. Changing the shading design may allow for a prevention of frost exposure without loss of dormancy, but further tests will be required.