C. Richer

Évaluation de la tolérance du Thuja occidentalis L. et de huit de ses cultivars aux conditions climatiques du nord-est canadien

Six successive plantations of Thuja occidentalis L. (from 1985 to 1990) were transplanted in different sites corresponding to different northeast Canadian climatic zones (2 to 5). Five cultivars of this species were planted in 1985 and three other cultivars in 1986. These plants were observed over a 5-yr period to validate the climatic zonal range attributed to the species and to determine the winterhardiness of the cultivars. Winter damage observed each spring indicated that Thuja occidentalis L. can survive in climatic conditions more severe than those suggested in the literature. However, survival varies among the cultivars studied. Woodwardii, Reidii, Wareana and Lutea showed a winterhardiness similar to the species. Pulcherrima showed the most damage. Little Champion, Smaragd and Fastigiata cultivars gave a response between the two other groups. Furthermore, growth in terms of height and width of the species and each cultivar was influenced by the different climatic conditions of each location. Key w...

Interprétation de la réponse de dix cultivars de potentilles évalués sous diverses conditions climatiques du nord-est canadien

Interpretation of the response often cultivars of Potentilla fruticosa evaluated under north-east Canadian climatic conditions. Can. J. Plant Sci. 84: 569-588. Rooted cuttings of 10 cultivars of Potentilla fruticosa L. were planted between 1984 and 1994 and evaluated over a 5-yr period in order to validate or determine their winterhardiness under different sites corresponding to different northeastern Canadian climatic zones (2 to 5). Based on the winter damage observed each spring, survival and usage potentials were not very different between the 10 evaluated cultivars. McKays White and Red Ace cultivars were the most damaged in the colder zone and their survival and usage potentials were established in zone 2b. For the others cultivars, these potentials were defined to the zone 2a. Moreover, the full ornamental expression potential was very variable between cultivars. It was limited by growth of plants, which was influenced by climatic conditions observed in each testing site.

Évaluation de l’endurcissement au froid et de la reprise de la croissance de quatre cultivars de rosiers de la Série ExplorateurMC

Des tests de congelation en conditions controlees ont ete realises au cours des automnes 1999 et 2000 sur des plants entiers de Rosa ‘Captain Samuel Holland’, de R ‘Champlain’, de R. ‘John Davis’et de R. ‘William Baffin’afin de determiner la temperature la plus froide a laquelle ils peuvent survivre. En general, les differentes parties des plants se sont endurcies au froid entre la premiere serie de tests (octobre), la deuxieme serie (novembre) et/ou la troisieme serie (decembre). Les TL50 associees a la survie des plants se rapprochent des T50 se rapportant aux dommages les plus severes survenus sur les racines et des TL50 se rapportant aux dommages observes a la base de la partie aerienne des plants. Les plants qui ont survecu aux temperatures se situant immediatement au-dessus des TL50 de la reprise accusent une diminution de croissance souvent tres importante. La TL50 de la reprise des plants du cultivar ‘Champlain’e tait de l’ordre de -14,5 °C lors de la troisieme serie de tests alors que celles des ...

Dommages hivernaux observés sur de jeunes plants d’Acer saccharinum L. sous différentes conditions agroclimatiques canadiennes

1Centre de recherche et de developpement en horticulture, Agriculture et Agroalimentaire Canada, 430, boul. Gouin, Saint-Jean-sur-Richelieu, Quebec, Canada J3B 3E6; 2Departement de phytologie, Faculte des sciences de l’agriculture et de l’alimentation, Universite Laval, Sainte-Foy, Quebec, Canada GIK 7P4; 3Departement de Mathematiques et de Statistique, Faculte des Sciences et Genie, Universite Laval, Sainte-Foy, Quebec, Canada GIK 7P4. Recu le 12 juin 2000, accepte le 20 septembre 2000.