HERBACEOUS PERENNIALS FOR URBAN LANDSCAPING IN FINLAND

In Finland, woody plants are widely used in landscaping. Herbaceous perennials, however, could offer more variation than woody ornamentals and also an economic and ecologic choice for annuals or lawn in parks and cemeteries. In 2005, MTT Agrifood Research Finland started a project aiming at increasing the use of perennials in urban landscaping, and the project will continue until 2010. The project aims at finding suitable species and combinations of species for different purposes and at establishing guidelines for low maintenance techniques based on plant ecology and sociology.
Information of the basic features, ecology and competition of various species is obtained from the field trials conducted at the MTT research stations and from trials set up in landscaping areas in six towns and three cemeteries in different climatic zones. The emphasis is, on one hand, on large species suitable for extensive plantings and, on the other hand, on low ground-covering species. The plant material originates from Finnish nurseries and botanical collections. A soil free from weeds is used. Detailed care of plants is avoided and treatments take place only a few times during the growing season. For traffic areas, perennials with good drought, heat and exhaust tolerance and a low growth habit are ideal, and they can be planted either as pot plants or mats. For use in cemeteries, perennials to replace annual flowers and grass on the graves are sought. The project also aims at finding large species and combinations of species suitable for extensive perennial areas and successful in the northern regions of Finland. On the basis of the results, specific guidelines are being prepared for the use of the 50-100 best-performing perennials.