Potentiel d’adaptation et de croissance d’arbustes ornementaux à fleurs évalués sous les conditions climatiques du Québec et du nord-est ontarien

Seven flowering cultivars of deciduous shrubs were evaluated for their winter hardiness and their growth potential to provide adequate recommendations regarding their adaptation to different climatic conditions. Plants were grown at eight sites in Quebec and one in northeastern Ontario in order to cover three broad biogeographic regions. Hydrangea paniculata ’Grandiflora’, Kerria japonica (L.) DC., Potentilla fruticosa ’Goldfinger’, Prunus × cistena N.E. Hansen, Prunus tomentosa Thunb., Viburnum opulus ’Compactum’ and Weigela hybrida ’Brystol Ruby’ were used. Potentilla and Viburnum were not affected by winter conditions at any of the sites, whereas Hydrangea, Kerria and Weigela did not survive at Kapuskasing. Our results indicated that Weigela was adapted to zone 5b only, whereas Kerria should not be recommended in any zone tested. Although the other species were adapted throughout Quebec, their production was superior in the Montreal region. Annual pruning of Kerria and Weigela was related exclusively t...