Miscanthus: Ornamental and Invasive Grass

Abstract

Miscanthus sinensis was investigated where it has naturalized and invaded native plant communities in southeastern Pennsylvania, the Washington, D.C. area, western North Carolina, and Iowa. Plants were identified; inflorescences were collected; seed was cleaned and tested for viability; and soil was collected for seed bank analysis. Many individuals were interviewed at each location. Locations were mapped to show miscanthus. The species or “wild type” Miscanthus sinensis that has naturalized at the above locations is rarely sold in the nursery trade. The numerous, popular, ornamental cultivars derived from this species are vegetatively propagated clones that are common in the nursery trade. Miscanthus is self-incompatible and sets seed only when two or more genotypes are grown together. Individual isolated plants set little seed. Plants of the wild type which have naturalized each represent a unique individual or genotype and thus set heavy seed, quite different from ornamental cultivars. Further complicating this is the high variability of seed set due to environmental conditions. Management guidelines were developed along with recommendations which include: Do not plant the species Miscanthus sinensis. Cultivars of the species, especially when two are more are grown together, represent a high risk for self-seeding in the Mid Atlantic states. Cultivars should only be planted in areas where they can be watched and managed for self-seeding. No miscanthus should be planted where it can seed into native areas, such as highways, fields, meadows, or wooded areas. A comprehensive website with identification, pictures, management guidelines, and recommendations was developed: http://horticulture.coafes.umn.edu/miscanthus .