Arboretum Mustila near Elimäki in Southern Finland was founded in 1902 as a test site for exotic conifer species. Today it remains a unique area of introduced horticultural plants in northern Europe. Nearly 100 conifer species, more than 200 broad-leaved tree species and numerous shrubs, vines, bulbs and perennials have been planted in the arboretum, covering 120 hectares.

Arboretum Mustila is especially famous for its rhododendrons and azaleas. In June a colourful sea of flowers can be seen in the Rhododendron Valley when hundreds of different species and hybrids are blooming. Another spectacular season of colours is in the autumn when the deciduous trees burst into a glow of red, orange and yellow.

Many of the conifers are planted in large stands rather than single specimens creating an illusion of woods in exotic countries. Stands of hemlocks, Western red-cedar, Pacific silver fir or cathedral-like Serbian spruce are the favourite places for many visitors throughout the year.