Japanese rose – Rosa rugosa

Japanese rose is a 0,5 to 1,5 metres tall shrub with large pink or sometimes white flowers. The surface of the leaves is wrinkled, from which the plant gets its Finnish name, “wrinkled rose”. In Finland, it can be seen as an ornamental plant in various plantings and on roadsides as well as an escapee in the environment, especially on the coastal areas.

The species reproduces from seeds and it also spreads vegetatively through rootstocks in its wide root system. Usually, the seeds do not germinate in the same autumn because of dormancy, which needs to be broken by cold stratification. However, to prevent its spreading from gardens to nature, it is worth collecting rose hips in the autumn. This reduces both the risk that birds will spread seeds and that fallen seeds will germinate in spring. It is worthwhile to collect the rose hips of Rosa Rugosa -varieties as well, because there is variation even in their seed production.