Адаптивный потенциал видов рода Spiraea L. в условиях Дендрологического сада им. И.М. Стратоновича

Abstract

This article presents the results of a comprehensive study of decorative flowering shrubs of the genus Spiraea (Spiraea L.). 7 species of Spiraea L. from the collection of the Dendrological Garden of Northern (Arctic) Federal University named after M.V. Lomonosov have been selected for analysis: Spiraea × Bumalda Burv, Spiraea ulmifolia Scop (L.) Maxim, Spiraea chamaedryfolia L., Spiraea salicifolia L., Spiraea nipponica var. tosaensis, Spiraea betulifolia Pall and Spiraea sericea Turcz. It has been established that the shrub height varies from 0.8 m (for Spiraea Bumalda Burv, Spiraea betulifolia and Spiraea nipponica var. tosaensis ) to 2.1 m (for Spiraea ulmifolia Scop (L.) Maxim and Spiraea sericea Turcz.). Spiraea ulmifolia Scop (L.) Maxim has the largest crown span (2.4 × 2.7 m) with a maximum number of 42 stems for a shrub. The compact shape of the shrub has been noted in Spiraea betulifolia Pall and Spiraea Bumalda Burv (1.0 × 1.3 and 1.0 × 1.1 m, respectively). While conducting phenological observations, it has been recorded that the first leaves of Spiraea sericea Turcz, Spiraea salicifolia L., Spiraea ulmifolia Scop (L.) Maxim and Spiraea nipponica var. tosaensis Maxim begin to appear in mid-May. The leaf blades of the remaining introduced species under study unfold with a difference of two weeks from the previously listed ones. It has been established that all the species of Spirea L. under study successfully tolerate the harsh northern climate (winter hardiness score I–II) and have become naturalized, which has been confirmed by the abundance of fruiting and the sowing quality of the seeds. According to archival data, the seeds of all the species of Spiraea L. under study ripen annually. The largest proportion of germinable seeds has been observed in Spiraea betulifolia Pall (92 %). High seed germination energy has been noted in Spiraea sericea Turcz and Spiraea betulifolia Pall. The period of seed germination for all Spiraea has been 15 days, except for Spiraea Bumalda Burv., which has been left on the bed for up to 20 days, however, the germination rate has been only 57 %, and a fifth of the tested seeds have been empty. The high quality of self-reproducing seeds leads to the conclusion that Spiraea sericea Turcz., Spiraea nipponica var. tosaensis, Spiraea betulifolia, Spiraea ulmifolia Scop (L.) Maxim and Spiraea salicifolia L. can be grown from seed stock. All the species under study are characterized by the full extent of adaptability. The decisive factor influencing the degree of adaptability of Spiraea is high winter hardiness of these plants. The adaptive capacity of introduced species determines the boundaries of the secondary distribution area. All the species under study can be recommended for northern city landscaping.