The dynamics of the species into collections of the north American and the Himalayan hills in alpinarium of Peter the Great Botanical Garden

Botanical gardens' collections of living plants are valuable not only because of their exhibitions, but also because of the data accumulated during introductions of new plants. Inventory allows to collect valuable material about introduction of different types of plants (species and taxa). Analysis of the available information allows to select and recommend advanced species (genus complex) for the needs of urbane floristics; the perennial herbaceous plants of mountain areas come in the first place. A new list of advanced ornamental and household plants is introduced in the article. The recommended plants can be used for urban gardening and various groundscape works, and for creation of seed orchards in the neighboring regions. The study of introduction results helps not only to determine the advanced species (and taxa), but to understand which spices will not be able to survive a long time in the new conditions (mainly because of the climate), for example in the North-West of Russia. Over the past 60 years, around 385 plants of 61 families has been introduced at the North American and Himalayan rock gardens of the Peter the Great Botanical Garden. In the 60s of the 20th century, the exposition of these rock gardens had nearly 130 species from 51 families, 20 years later – 254 plants of 55 families. In the beginning of the 21st century, there were 249 taxa of the 52 families. Since 2010, the Alpinarium had to undergo a major reconstruction following the restoration and addition of the collection. As of 2015, the exposition of the North American and Himalayan rock gardens has 200 species of 54 families.