Common reed (Photo by Wikimedia Commons)
Common reed is a large perennial grass that grows up to five metres tall. Although it grows in all wetlands, it is often found growing in roadside ditches.
Originally from Europe and Asia, this species has invaded many wetlands in eastern North America. This invasive species outcompetes native wetland plants, and is a serious threat to biodiversity.
Once introduced into an area, the plant's roots spread far and wide below wetlands in a vast network of rhizomes. Its seeds are easily wind-dispersed, thereby allowing common reed to further invade other habitats.
How is it identified?
Although it grows in all wetlands, it is often found growing in roadside ditches. Common reed is identified by its leaves, which are blue-green in colour and wider than one centimetre and grow in sheaths adhered to the stem. The flowers, which appear in late summer, grow in a dense cluster.
How does it grow?
Its seeds are easily wind-dispersed, thereby allowing common reed to further invade other habitats.
Where does it grow?
Common reed grows in wetlands in temperate and tropical regions.
What does it threaten?
Thick stands choke out native plants' growth, provide poor wildlife habitat and disrupt natural wetland functions. Dead stalks from previous years’ growth can increase fire risk. Common reed grows so tightly that animals such as turtles and snakes can't use the wetland anymore. Although some birds may nest in its thickets, the plant does not provide ideal habitat since common reed doesn't support enough insects for them to feed their young.
What is NCC doing to control this invasive species?
In southwestern Ontario, the Nature Conservancy of Canada (NCC) is actively removing this species on a number of properties. Because the roots of this plant grow so deep, it is difficult to remove, and involves a few steps:
- Ideally, the dead plant material is burned during the winter or very early spring. This removes the material, and kills some of the seeds.
- The plant is then allowed to grow up from the large root system all summer, and is sprayed with dilute herbicide in the early fall. This kills the roots, so the plant does not regrow during the following year.
Burning itself does not really harm the plant, but it makes it much easier to work with and reduces the volume of herbicide required. One method is to burn the plant over several seasons.
In Middle Point woods on Pelee Island, NCC staff have almost eradicated an 800-metre-long population of the plant. The cleared area now supports at least 20 native plants, and staff have seen snapping turtles, and Lake Erie watersnakes and eastern foxsnakes (all species at risk) using the area. Further evidence of their success has been the natural establishment of a swamp rosemallow plant — our native hibiscus, a species at risk with beautiful, large pink flowers.
How can you help?
Read the Ministry of Natural Resource's Best Management Practices here >
Everyone can help to win the battle against alien invasive species. Here are some ways you can help:
- Professional help is recommended. The most effective method is a three-step combination of spraying with herbicide, mowing and controlled burning repeated over three years or until the patch is eradicated.
- Dispose of yard waste properly. Dumping yard waste in natural areas can introduce alien invasive species that will thrive and spread. Even leaf piles can be problematic, as dumped piles can smother native vegetation. Contact your municipality to find out how to dispose of yard waste properly.
- Plant native species in your garden! There are lots of beautiful native species that attract native butterflies and birds, making your garden twice as beautiful. Native species are also adapted to our climate and often require less rigorous care than exotic species.
- Report sightings of invasive plants to your local stewardship council. Finding these invasions early is a key to eradicating them.
- Clean your shoes or bicycle tires when moving between designated trails in different areas. Invasive plants are often spread accidentally from seeds stuck in treads.