Watermilfoil: The Beautiful but Controversial Aquatic Plant
If you’ve ever gazed into a pond and admired those feathery, almost ethereal underwater plants swaying gently in the current, you might have been looking at watermilfoil (Myriophyllum). This aquatic perennial has a complicated reputation in the gardening world – beloved by some for its delicate beauty, yet viewed with suspicion by others due to its aggressive tendencies.
What Exactly is Watermilfoil?
Watermilfoil is a genus of aquatic plants that spend most of their lives completely submerged underwater. These perennial forbs lack woody tissue and are characterized by their incredibly fine, feathery leaves that look almost like underwater ferns. The foliage is so finely divided that it creates a soft, cloud-like appearance beneath the water’s surface.
As forbs, these plants have their growing points at or below ground level, allowing them to survive harsh winters and return each growing season. Some species produce small, inconspicuous flower spikes that emerge above the water surface during blooming season.
Where Does Watermilfoil Call Home?
The geographic story of watermilfoil is quite complex. The genus has a mixed native status across North America – it’s native to Greenland and St. Pierre and Miquelon, but has an undefined status in Alaska, Canada, and the lower 48 states. In Hawaii, it’s considered a non-native species that has established itself and reproduces without human intervention.
Currently, you can find various watermilfoil species growing across an impressive range that includes nearly every U.S. state and Canadian province, from Alabama to Alaska, and from British Columbia to Newfoundland.
The Beauty and the Beast
There’s no denying that watermilfoil can be absolutely stunning in the right setting. Its feathery underwater foliage creates incredible texture and movement in water gardens, making it a favorite among aquatic gardening enthusiasts. The plant’s delicate appearance adds a soft, naturalistic feel to ponds and water features.
However – and this is a big however – watermilfoil comes with some serious caveats. In Missouri, for example, it’s classified as having Nuisance (DOC) invasive status, meaning it can cause ecological and economic problems.
Wildlife Benefits: A Mixed Bag
While watermilfoil does provide some benefits to wildlife, they’re relatively modest. According to research, water birds use watermilfoil for only 2% to 5% of their diet and rely on it sparsely for cover. So while it’s not completely without merit for wildlife, it’s certainly not a powerhouse native plant in terms of ecological support.
Should You Plant Watermilfoil?
This is where things get tricky. Given watermilfoil’s invasive tendencies and potential to cause ecological disruption, most native plant experts would recommend proceeding with extreme caution – or better yet, choosing alternatives altogether.
If you’re determined to include aquatic plants in your water garden, consider these native alternatives instead:
- Native pondweeds (Potamogeton species)
- Wild celery (Vallisneria americana)
- Coontail (Ceratophyllum demersum)
- Native water lilies (Nymphaea species)
If You Already Have Watermilfoil
If watermilfoil has already established itself in your pond or water feature, management is key. The plant can spread rapidly through fragmentation, so regular maintenance and monitoring are essential. Consider consulting with local extension services or aquatic plant management professionals for the best removal strategies that won’t harm other aquatic life.
Growing Conditions (For Educational Purposes)
Should you encounter watermilfoil in natural settings, you’ll typically find it in permanent water bodies with full sun to partial shade conditions. As an aquatic plant, it requires year-round water and can adapt to various water depths and conditions – which unfortunately contributes to its invasive success.
The Bottom Line
While watermilfoil might catch your eye with its delicate, feathery beauty, its potential for ecological disruption makes it a plant to admire from afar rather than invite into your garden. Instead, explore the wonderful world of native aquatic plants that can provide similar aesthetic benefits while supporting local wildlife and maintaining ecological balance.
Remember, the best gardens work in harmony with nature rather than against it – and sometimes that means saying no to a pretty plant with problematic tendencies.
