Modeling Cold Hardiness of Red-osier Dogwood

Effects of temperature on cold acclimation and deacclimation of red-osier dogwood (Cornus sericea L. syn. Cornus stolonifera Michx.) plants were determined at different stages of plant development. Results were used to develop models for predicting stem hardiness. Acclimation and deacclimation rates were related to temperature and plant developmental stage (expressed as degree growth stage, °GS). Decreasing temperature promoted increasing acclimation. Maximum acclimation rates in the temperature range of 5° to 20°C occurred at maximum rest (270°GS). During the decreasing rest phase (270 to 315°GS), deacclimation occurred at temperatures from 7° to 20°C. At earlier stages of development (315° and 335°GS) during the quiescent phase (315 to 360°GS), 5°C was the only temperature that promoted hardiness, whereas at a later stage (341°GS) all temperatures tested caused deacclimation. The models, using bihourly temperatures and accumulating °GS, predicted hardiness within an average deviation of 4.7°C.