Cotton candy grass (Muhlenbergia capillaris) is an ornamental grass celebrated for its distinctive airy, pinkish-purple plumes that emerge in late summer and fall. It creates a cloud-like effect in gardens, earning its common name. Gardeners often question its potential invasiveness.
Defining Invasive Plants
An invasive plant is a non-native species introduced to an ecosystem that causes, or is likely to cause, environmental, economic, or human health harm. These plants spread aggressively, outcompeting native flora due to traits like rapid growth, prolific seed production, efficient seed dispersal, and a lack of natural predators. Their unchecked spread can reduce plant diversity, degrade wildlife habitat, and impact water quality.
Cotton Candy Grass and Invasiveness
Muhlenbergia capillaris is native to a significant portion of eastern North America. Within its native range, it is generally a well-behaved perennial. However, outside its typical habitats or in favorable garden conditions, it can exhibit aggressive self-seeding and spreading tendencies. This leads some to characterize it as “weedy” or “aggressive” rather than truly “invasive” in all contexts.
The plant produces abundant, easily dispersed seeds, contributing to its spread in managed landscapes. While clumping, its self-seeding can lead to new plants in unintended areas. Its status varies by region; some areas list it as a concern due to its aggressive nature, particularly in disturbed soils, while in others, it remains a popular ornamental. For instance, though widely native, it is endangered or extirpated in some northern states like Connecticut, Indiana, and Pennsylvania.
Managing Potential Spread
Gardeners can employ several strategies to manage cotton candy grass’s potential spread. Deadheading, which involves removing spent flower plumes before seeds mature, significantly reduces unwanted self-seeding. Regular monitoring allows for prompt removal of any volunteer seedlings.
Dividing mature clumps every few years helps manage the plant’s size and vigor. This is best done in early spring by digging up and splitting the clump into smaller sections. Physical barriers, such as edging around planting beds, can also help contain the root spread of aggressive clumping grasses.
Responsible Gardening Choices
Making informed plant selection decisions is crucial for responsible gardening. Gardeners should research a plant’s invasiveness status in their specific region before planting, as a species benign in one area might be problematic elsewhere. Consulting local agricultural extension offices or native plant societies provides valuable, region-specific information.
Considering native alternatives with similar aesthetic appeal, but without aggressive spread, is beneficial. For example, other native grasses like Little Bluestem (Schizachyrium scoparium) or Prairie Dropseed (Sporobole heterolepis) offer texture and interest. These native choices support local ecosystems by providing food and habitat for wildlife, contributing to a healthy, biodiverse garden.