Curly Pondweed: Why This Aquatic Plant Should Stay Out of Your Water Garden
If you’re planning a water garden or pond feature, you might come across curly pondweed (Potamogeton crispus) and think its wavy, translucent leaves look pretty appealing. But before you consider adding this aquatic plant to your landscape, there’s something crucial you need to know: this innocent-looking plant is actually a notorious troublemaker that’s wreaking havoc on waterways across North America.
What is Curly Pondweed?
Curly pondweed is a perennial aquatic plant that lives completely submerged in water. True to its name, this plant has distinctive wavy, ribbon-like leaves that give it a curly appearance underwater. The foliage ranges from bronze to reddish-green, and while it might look attractive rippling in the current, don’t let its beauty fool you.
This plant is classified as a forb – essentially an herbaceous plant without woody stems. It grows rapidly during spring, summer, and fall, forming dense underwater mats that can completely take over aquatic environments.
The Problem: It’s Not From Here
Here’s the big issue: curly pondweed isn’t native to North America. Originally from Europe, Asia, and Africa, this plant was introduced to our continent and has since spread like wildfire. It now grows in virtually every U.S. state and several Canadian provinces, from Alberta to Wyoming and everywhere in between.
Why You Should Avoid This Plant
Curly pondweed isn’t just non-native – it’s actively harmful. Multiple states have classified it as invasive, and here’s why that matters:
- Connecticut: Listed as invasive and prohibited
- Michigan: Classified as invasive and restricted
- North Dakota: Designated as an aquatic nuisance species
- Wisconsin: Listed as restricted
- Alabama: Classified as a Class C noxious weed
This plant spreads aggressively through fragmentation – meaning tiny pieces can break off and start new colonies elsewhere. It also produces special winter buds called turions that help it survive harsh conditions and spread to new locations.
The Environmental Impact
When curly pondweed takes over a water body, it creates dense underwater mats that can:
- Crowd out native aquatic plants that wildlife depends on
- Reduce oxygen levels in the water
- Interfere with recreational activities like swimming and boating
- Alter the entire aquatic ecosystem
Growing Conditions (For Identification Purposes Only)
If you encounter this plant, here’s how to identify it. Curly pondweed thrives in:
- Full water submersion (it’s an obligate wetland species)
- USDA hardiness zones 3-10
- pH levels between 6.4 and 8.5
- High moisture environments with poor drainage
- Areas with high salinity tolerance
The plant has a rapid growth rate and can quickly dominate water features. It’s intolerant of shade but thrives in sunny aquatic environments.
Better Alternatives for Your Water Garden
Instead of risking the ecological damage that comes with curly pondweed, consider these native aquatic plants for your water features:
- Wild celery (Vallisneria americana): Provides similar underwater texture
- Coontail (Ceratophyllum demersum): Excellent oxygenator
- Water milfoil native species: Beautiful feathery foliage
- Pondweed native species: Similar appearance without the invasive behavior
What to Do If You Find It
If you discover curly pondweed in your area, don’t try to remove it yourself – you might accidentally spread it further. Instead, contact your local extension office or natural resources department for guidance on proper removal and disposal.
The Bottom Line
While curly pondweed might seem like an attractive addition to water gardens with its unique wavy leaves and rapid growth, it’s simply not worth the risk. This invasive species can quickly escape cultivation and cause serious environmental damage to local waterways. When it comes to aquatic plants for your landscape, stick with native species that will beautify your space while supporting local ecosystems rather than destroying them.
Remember: the best water gardens work with nature, not against it. Choose plants that belong in your region, and you’ll create a beautiful, sustainable aquatic feature that benefits both your landscape and the environment.
