Japanese spirea (Spiraea japonica) is an attractive and widely used landscape shrub. But like some other garden staples such as barberry, burning bush and Norway maple, it can be invasive in areas of the eastern United States, crowding out native plants and disrupting ecosystems.
But ecologically responsible gardeners may not need to say goodbye to this useful plant entirely. Recent research at Montana State University has identified three sterile cultivars of Japanese spirea, ones that do not set seed and therefore can't spread and become a threat to native vegetation. 'Crispa' is a 2-3' tall shrub with deep pink flowers and twisted crinkled foliage; 'Dart's Red' has deep,carmine-red flowers and pinkish-red new growth on a 2-3' tall shrub; 'Neon Flash' is of similar size, with bright neon-red flowers that are produced over a long period. (You may see these listed as Spiraea x bumalda cultivars, instead of S. japonica).
To find out which plants are considered invasive in your part of the country go to: National Invasive Species Information Center .