Some people love Duckweed, but if you are reading this, you probably hate it!
Getting rid of Duckweed can be tricky, but with the right approach, it’s manageable. By understanding how it grows and applying proven control methods, you can keep it from taking over your pond. In this quick guide, we have shared effective strategies to help you maintain a balanced aquatic environment.
Duckweed Information
Duckweed prefers nutrient-rich ponds, especially those with decaying leaves that create stratification. The black, smelly sludge at the bottom serves as its primary food source. Older, undisturbed ponds are more prone to duckweed infestations, often alongside watermeal, a smaller but equally aggressive plant.
If you don’t control Duckweed on time, it can quickly cover the pond’s surface, reducing oxygen levels and harming fish and beneficial aquatic plants. Familiar nutrient sources contributing to its growth include geese droppings, agricultural runoff, lawn fertilizers, and malfunctioning septic systems.
For effective control, management efforts should start early in the spring. Completely clearing a heavily infested pond can take years, but ponds with natural water movement from wind or currents tend to have fewer issues and require less intervention.
Is Duckweed a Weed?
Yes and no.
Native duckweeds play a crucial role in aquatic ecosystems. They provide food for ducks, fish, and the larvae of small China-mark moths, which build floating cases from duckweed fronds. A dense layer of Duckweed also offers shelter for aquatic invertebrates and spawning amphibians to create a thriving habitat for pond life.
Beyond its wildlife benefits, Duckweed helps control algae by competing for nutrients and can even improve water quality by absorbing pollutants. While often seen as a nuisance, this tiny plant is essential in maintaining a balanced pond environment.
Do I Need to Get Rid of Duckweed?
Regular duckweed control is essential to prevent it from smothering ornamental pond plants. However, since Duckweed provides food and shelter for wildlife, the goal should be to manage its growth rather than eliminate it. Keep Duckweed at a balanced level to maintain a healthy pond ecosystem without overwhelming the water’s surface.
How To Get Rid Of Duckweed?
You can’t eliminate Duckweed, and it’s not even necessary for a healthy pond. To remove excess and prevent it from becoming a nuisance, try these methods:
Quarantine new pond plants: Before adding them to your pond, quarantine them by keeping them in a bucket of water for a few weeks. If Duckweed appears, remove it by hand until the water stays clear.
Remove Duckweed by hand: Use a net or rake to scoop Duckweed from the water regularly. During summer, remove it weekly since it can double in just a few days. Add the removed Duckweed to your compost or green waste bin.
Use a floating boom on larger ponds: Sweep a boom from end to end to gather Duckweed, which is easier to remove with a net. Use a simple wooden batten or an old pool noodle, or get a specialist boom from a pond supplier.
Install a fountain: Disrupt the water surface with a fountain to make it harder for Duckweed to grow and spread.
Stock your pond with floating-leaved pond plants: Duckweed struggles to compete with other floating plants like water lilies. Keeping your pond well-stocked helps control Duckweed while providing shelter for pond wildlife.
Remove debris: Leaves and rotting vegetation add nutrients to the water, fueling duckweed growth. Place mesh over your pond in autumn to catch falling leaves, or use a hand net to remove debris.
Create shade over your pond: Duckweed thrives in full sun, so slow its growth by planting tall marginals along the south bank of your pond.
Fit stop-boards at upstream inlets: Block duckweed from entering your pond by installing stop-boards at upstream inlets.
Introduce duckweed grazers: In large ponds, add fish like goldfish, koi, or grass carp, or keep water birds like domestic ducks to help control Duckweed naturally.
Should I Use Weedkiller?
No chemical treatments or weed killers are approved for home gardeners to control Duckweed. Managing Duckweed can be time-consuming, but the correct manual and natural methods effectively control its growth. Regular maintenance helps prevent Duckweed from overtaking your pond without harming the ecosystem.
