Eräiden puuvartisten koristekasvien talvehtimisesta Viikissä, Jyväskylässä, Kauhajoella ja Rovaniemellä

Authors

• Erkki Kaukovirta Helsingin yliopiston puutarhatieteen laitos

DOI: https://doi.org/10.23986/afsci.71689

Abstract

Most of the available information about winterhardiness of ornamentals in Finland is based on separate observations in restricted areas. In order to get more comparable information, 37 different varieties of deciduous shrubs, 12 varieties of conifers and 62 varieties of perennials were planted at four different locations representing the following latitudes: 60° 10’, 62° 15’ (central Finland), 62° 25’ (West Finland) and 66° 15’. The overwintering of the deciduous shrubs and conifers during the first winters after planting is reported in this paper. The number of plants at the beginning of the experiment and the overwintering of these plants can be seen in Tables 3–7. The weather conditions during the wintering periods are reported in Tables 1 and 2. The observations made indicated that even the varieties which are considered to possess good winterhardiness in these latitudes are sensitive to winter damage during the first winters after the planting. The main cause of winter damage seemed to be the length of the period during while the plants were subjected to severe cold. As the number of days when the temperature was below 20° C increased, the occurrence and severity of winter damage increased. Short, often extremely severe cold spells did not have so great an effect on the overwintering, as can be seen by comparing Tables 1 and 3–6. The protection of a deep snowcover appeared to be of great importance for overwintering particularly during the first two winters after the planting. The plants which became established and were growing reasonably well by 1965 are marked with an asterisk before the name in Tables 3–6.