Winter in Tennessee brings frosty mornings, bare trees, and, for many, a welcome pause from spring and summer yardwork. But if you’re a pond owner, you might be wondering what happens to the algae and aquatic weeds you wrestled with earlier in the year. Do they die off entirely, or are they just lying in wait for warmer weather?
At Aquatic Weed Wizards (AWW), we’re often asked how Tennessee winters impact pond management. Let’s take a dive into what winter really means for the underwater world.
Winter’s Frost vs. Aquatic Weeds: Who Wins?
Tennessee’s winters, while milder than in northern states, can get cold enough for frost and occasional freezes. Many people think that these temperatures kill algae and aquatic weeds outright—but that’s not entirely true. Even when the above-ground growth wilts or the pond’s surface ices over, many species are surprisingly resilient.
- Perennial Aquatic Plants: Weeds like watermilfoil or coontail may appear dormant in the winter, but their root systems and submerged growth often survive. These plants can recover quickly in the spring, sprouting fresh growth as temperatures rise.
- Annual Plants: Weeds such as duckweed or water hyacinth are typically annual plants, meaning they die off at the season’s end. However, their seeds or spores can overwinter in the sediment and wait for spring to sprout again.
Algae: Winter’s Persistent Problem
Unlike rooted plants, algae come with their own set of challenges during the colder months:
- Planktonic Algae: These are the tiny organisms that give ponds a green, cloudy appearance during warm weather. When temperatures drop, their growth slows significantly, but they don’t disappear entirely. If nutrients like nitrogen and phosphorus are still abundant in the water, algae may linger and even bloom during mild winters.
- Filamentous Algae (Pond Scum): While freezing ponds can limit its spread, filamentous algae often remain viable along the bottom of the pond or in areas with standing water. When spring arrives, this “scum” can rapidly float to the surface as it begins to grow again.
Think of algae as hibernating rather than dying—especially in Tennessee’s climate, where freezes might be brief.
Why Cold Alone Isn’t Enough
The key thing to understand about Tennessee winters is that they don’t always last long enough or get cold enough to kill aquatic weeds and algae completely. For example, a thick ice sheet can block sunlight and suppress plant growth, but ponds here rarely freeze to that extent. Many resilient aquatic weeds and algae thrive in low light and simply wait out the chill.
Instead, winter provides a short window of slowed activity—not eradication.
What Can Tennessee Pond Owners Do This Winter?
Winter may not eliminate algae and aquatic weeds, but it actually offers a golden opportunity for preventive management. Here’s what you can do now to make next spring and summer more manageable:
- Remove Plant Debris: Dead or dying weeds may still float or settle on the pond’s bottom. Cleaning this debris prevents it from contributing to nutrient buildup, which feeds algae.
- Inspect Your Pond: With reduced weed and algae cover, winter makes it easier to spot trouble areas where sediment buildup, erosion, or unmanaged plants might need attention.
- Adjust Nutrient Inputs: Runoff from nearby sewer systems, manure piles, or lawn fertilizers often serves as a food source for aquatic weeds year-round. Evaluate nutrient sources that might be entering your waterway during winter rains.
- Seek Professional Advice: Winter is the perfect time to plan. At Aquatic Weed Wizards, we offer custom pond management strategies designed to target algae and invasive plants before they bounce back. By acting now, you’ll start the new year with a healthier, clearer pond.
Don’t Let Your Guard Down This Winter
While winter might seem calm on the surface, your pond’s ecosystem is still very much alive. Algae and aquatic weeds may be slowed, but they’re not gone. Staying proactive during this season will yield massive benefits for the year ahead.
At Aquatic Weed Wizards, we’re here to guide Tennesseans through every season of pond care. If your pond is in need of some winter TLC—or you’d like a head start on spring growth—contact us today. Together, we can keep your waters clean, clear, and ready for what’s next.
