The evaluation of the stability of development by the level of fluctuating asymmetry (FA) has been widely used in various studies. For a number of objects, such approach is impossible. We propose an approach for assessing the FA level for leguminous plants by the example of the Siberian pea shrub (Caragana arborescens Lam., 1785) in the conditions of Kazan. The obtained results showed the variability of the FA level in conditions of the multi-storey building and forest park area. The highest FA value was found in the forest-park area. The relationship between the level of FA and reproductive parameters (the relative magnitude of actual fertility) was found. The obtained results give us grounds to assume that the proposed methodological approach allows us to assess the ecological state of the territory with the help of the FA level in the environmental monitoring system in the city.