COLD HARDINESS ESTIMATES FOR TEN HYDRANGEA TAXA

Ten Hydrangea macrophylla (Thunb.) Ser. and H. serrata (Thunb. ex J.A. Murr.) Ser. taxa were evaluated for midwinter cold hardiness, acclimation, and deacclimation to identify taxa with superior cold tolerance. Hydrangea macrophylla ‘Endless Summer’, ‘Mariesii Variegata’, and ‘Veitchii’ acclimated later than all other taxa. ‘Générale Vicomtesse de Vibraye’ acclimated first, and was cold hardy to –6 °C by 28 Sept.
The greatest cold hardiness in all taxa occurred on 5 Jan.
Maximum cold tolerance in all taxa was within a 6 °C range with ‘Endless Summer’ being the least cold hardy (–18 °C), while ‘Dooley’, ‘Générale Vicomtesse de Vibraye’, ‘Mme.
Emile Mouillère’, and H. serrata ‘Bluebird’ possessed the greatest cold hardiness (–24 °C) on 5 Jan.
On 1 Mar., ‘Ayesha’ and ‘Mariesii Variegata’ survived only 4 °C while all other taxa survived at least –6 °C.

XXVI International Horticultural Congress: Environmental Stress and Horticulture Crops

J.A. Adkins, M.A. Dirr, O.M. Lindstrom

deacclimation, acclimation, Hydrangea paniculata, Hydrangea arborescens

https://doi.org/10.17660/ActaHortic.2003.618.17