Development of the North of Western Siberia is progressing rapidly. It is accompanied by the growth and emergence of new settlements. Creating green spaces in the harsh conditions of the North is a responsible thing. To work out a sustainable trees and shrubs assortment 15 experimental sites were laid in 2013-2016. They are located in different climatic conditions of the North of Western Siberia (in tundra, forest-tundra, northern and middle taiga). More than 6400 specimens of trees and shrubs of 313 taxa (species, varieties) and cultivars (28 families) were tested over the period. The experience showed that the mass loss of plants was associated with the underestimation of some agrotechnical features and with weather conditions. Using only the experimental test data for the development of a plants sustainable assortment is not effective. The combination of ecogeographical analysis and observations gives good results. The establishment and maintenance of experimental sites network is an important element of successful work to create a sustainable assortment of woody plants for territories with harsh climate.