Duckweed Control

Duckweed (Lemnaoideae) is something I am actually very fond of...of course when a large pond is infested with this plant it is no fun but in smaller water gardens and backyard ponds duckweed can actually be a helpfull addition to the ecosystem! Myself, I've actually gone to the garden store and bought a container full of duckweed to add to my backyard pond...it cost me $5 and my wife asked me if I was losing my marbles because duckweed can be found in almost any farm dugout or stagnant swamp in the area! I am asked at least twice a week about methods for controlling duckweed and other aquatic plants and algae of course.

In a large pond duckweed can be an invasive plant that can cover the surface quickly and it often is a real nuisance for the pond owner who suddenly can't see anything in the pond!

Before we kill the duckweed with an aquatic herbacide, yes there are some good algaecides that can eliminate duckweed from a pond, lets make sure we actually do want to do it because this floating plant is actually a real wonder of the pond! Duckweed can absorb a whole bunch of nutrients from the water and will provide a great umbrella of shade for fish...so it will keep waters cooler and also suck out phosphates from the pond. These phosphates and other nutrients are the junk in the pond that cause the big blooms of floating green algae and algae that grows on the bottom of the pond.

Why You May Love Duckweed:
Duckweed is a small delicate plant that drifts on the pond surface, filling in spaces between the lily pads, creating a lovely green blanket across the pond. This provides a lush habitat for frogs and fish and insects of the pond. The layer of floating aquatic plants provides shade to the pond keeping it cooler during stifling hot days of overhead sun. Waterfowl will feed voraciously on the duckweed thus nest nearby and live in the pond. Duckweed grows rapidly and absorbs mineral elements like nitrogen and phosphates from the water column so it can be an important part in the aquatic rehabilitation of any pond or lake as these nutrients can cause problems like algae and cyanobacteria. It is especially good at removing ammonia from ponds. Beyond providing shade for fry bluegill and a place to live for bullfrogs the duckweed helps reduce evaporation which can be a problem in a clear pond without any cover to slow the rate of pond evaporation. Sometimes just the rich green color of the plant alone is enough to make us feel like our pond is a healthy and natural aquatic system! A bit like a stained glass window on the pond, duckweed is a wonderful and beautiful plant, that with a bit of understanding and acceptance is actually a very beautiful thing!


Why You May Hate Duckweed:
Duckweed is an invasive and agressive aquatic weed that can rapidly multiply and if conditions are right will completely cover a pond with a thick green cover of tiny green plants that are only a few milimeters in size. The thick matting of pond weed can literally choke out a pond and if conditions, temperatures and nutrient levels are right can completely hide the water and create a cover that hides the pond and makes it almost unpleasant. Frogs and ducks and turtles will live in what looks like a swamp! Maybe it provides food for swans and geese and a mallard duck or two but it can choke out oxygen levels.


There are Only Two Ways of Getting Rid of Duckweed and Removing Blanket Weed (beyond just ignoring it)
1 - The Natural Way
If the pond is small enough just the best way to remove the small little flowering plant known as duckweed is to use a fine meshed net and just manually remove it day by day, hour after hour, until there is none left. Of course it is really tough to completey eradicate the problem but you can keep it under control just like keeping the dandelions out of the vegetable garden! You need a net with a long handle or a good quality aquatic rake to harvest this pond weed if you want to deal with this problem naturally or of course you can invite a family of ducks or geese or swans into your pond and they will love the free food supply offered by these floating flowering plants but you will still need the manual removal...if you don't want to accept the duckweed or don't want to perform the manual work or invite the Duckworth family into the pond then you need to go to the next option...

2 - The Chemical Way
Aquatic algaecides and herbicides are very effective at controlling duckwweds and other unwanted invasive pond species. You should understand that such algae problems, well...it's not reaslly an algae but an aquatic weed plant, if they are treated with herbiceds can lead to a dependance or resistance and scientists generally agree that chemical selection pressure that is applied applied to aquatic weed populations for a long enough period of time eventually leads to resistance. This means that while the chemical pond weed killer may work quickly and effectively for the first few years, unless you are adding a positive treatment with aeration and natural beneficial bacteria you will just be "chasing the dragon" so to speak!

Herbicides and Chemicals for Killing Duckweed and Pond Weeds White Cap Selective Herbicide Control aquatic weeds and grasses in fresh water ponds, lakes, and drainage/irrigation canals with WhiteCap™ SC selective herbicide, a proven reformulation of the popular active ingredient fluridone. WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including duckweed. Controls: Duckweed, Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, and Coontail See The List of Aquatic Weeds that White Cap SC will control before you buy. Email us if you're not sure! DOWNLOAD THE WHITE CAPFULL INSTRUCTION, WARNING & WARNINGS 75' x 75' Pond (.13) Acre 4 ft avg depth. - Amount required: 4 Ounces 105' x 105' Pond (.25) Acre 4 ft avg depth. - Amount required: 8 Ounces 148' x 148' Pond (.50) Acre 4 ft avg depth. - Amount required: 16 Ounces 208' x 208' Pond (1.0) Acre 4 ft avg depth - Amount required: 32 Ounces

8 Ounce Supply - White Cap Highly-Selective Duckweed Herbicide - $229 Price includes shipping. Item # PR-WC8 Apply 8 ounces per 600,000 gallons (1.9 feet acres) approx. Control aquatic weeds and grasses in fresh water ponds, lakes, and drainage/irrigation canals with WhiteCap™ SC selective herbicide, a proven reformulation of the popular active ingredient fluridone. WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including duckweed. Controls: Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and Duckweed 16 Ounce Supply - White Cap Highly-Selective Duckweed Herbicide - $439 Price includes shipping. Item # PR-WC16 Apply 8 ounces per 600,000 gallons (1.9 feet acres) approx. Apply 16 ounces per 1.2 million gallons (3.7 feet acres) approx. Control aquatic weeds and grasses in fresh water ponds, lakes, and drainage/irrigation canals with WhiteCap™ SC selective herbicide, a proven reformulation of the popular active ingredient fluridone. WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including duckweed. Controls: Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and Duckweed 32 Ounce Supply - White Cap Highly-Selective Duckweed Herbicide - $799 Price includes shipping. Item # PR-WC32 Apply 8 ounces per 600,000 gallons (1.9 feet acres) approx. Apply 16 ounces per 1.2 million gallons (3.7 feet acres) approx. Apply 32 ounces per 2.5 million gallons (7.7 feet acres) approx. Control aquatic weeds and grasses in fresh water ponds, lakes, and drainage/irrigation canals with WhiteCap™ SC selective herbicide, a proven reformulation of the popular active ingredient fluridone. WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including duckweed. Controls: Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and Duckweed

128 Ounce (1 Gallon) Supply - White Cap Highly-Selective Duckweed Herbicide - $1,795 Price includes shipping. Item # PR-WC128 Apply 32 ounces per 2.5 million gallons (7.7 feet acres) approx. Apply 64 ounces per 5 million gallons (15 feet acres) approx. Apply 128 ounces per 10 million gallons (31 feet acres) approx. Control aquatic weeds and grasses in fresh water ponds, lakes, and drainage/irrigation canals with WhiteCap™ SC selective herbicide, a proven reformulation of the popular active ingredient fluridone. WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including duckweed. Controls: Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and Duckweed

Vascular Aquatic Plants Controlled by WhiteCap Floating Plants Emersed Plants Submersed Plants Shoreline Grasses common duckweed (Lemna minor) spatterdock (Nuphar luteum) bladderwort (Utricularia spp.) paragrass (Urochloa mutica) water-lily (Nymphaea spp) common coontail (Ceratophyllum demersum) common elodea (Elodea canadensis) egeria, Brazilian elodea (Egeria densa) fanwort, cabomba (Cabomba caroliniana) hydrilla (Hydrilla verticillata) naiad (Najas spp.) pondweed (Potamogeton spp., except Illinois pondweed) watermilfoil (Myriophyllum spp., except variable-leaf milfoil) DOWNLOAD THE WHITE CAP LABEL WITH APPLICATION INFO IN PDF FORMAT Available only in USA. In certain states, herbicides and algaecides are restricted. Secure Shopping with Credit Card or Paypal® using the Secure Servers of Paypal®

General Application of White Cap SC Aquatic Herbacide & Algaecide

Susceptible aquatic weeds absorb WhiteCap SC through the shoots and roots. For effective control, contact of WhiteCap with the target plant must be maintained for at least 45 days. Effective control is reduced if conditions exist that dilute the concentration of WhiteCap in the water to below labeled rates. Apply WhiteCap as a surface spray or subsurface injection at rates between 10 and 90 ppb for single applications, or if multiple applications are made, do not exceed 150 ppb per growing season.

Water treated with WhiteCap SC at rates greater than 5 ppb must not be used for irrigation of certain crops and newly seeded turf. If the concentration of WhiteCap is less than 10 ppb, established tree crops, established row crops or turf can be irrigated with WhiteCap treated water. Do not apply WhiteCap at rates greater than 20 ppb within ¼ mile of any functioning potable water intake.

WhiteCap effectively controls a wide range of floating, submersed and emersed aquatic vegetation, including Hydrilla, Bladderwort, Watermilfoil, Naiad, Elodea, Water-lily, Pondweed, Coontail and Duckweed. Selective control. At low use rates, it is safe for most native beneficial aquatic plants; WhiteCap SC selectively removes the nuisance plants, while having little impact to desirable species

Complete control.
Readily moves and disperses throughout the water column, providing complete and thorough control of target nuisance aquatic weeds Slow control. Works slowly to remove excessive aquatic weeds with minimal impact to aquatic ecosystems No human or livestock use restrictions. Water treated is potable water safe and may be used immediately for human recreation and for watering livestock

Low use rates provide for cost-effective aquatic plant control
DOWNLOAD THE WHITE CAP COMPLETE INSTRUCTIONS IN PDF FORMAT

Eurasian Watermilfoil - Invasive Plants: Changing the Landscape of America
Federal Interagency Committee for the Management of Noxious and Exotic Weeds.
Identification/Description; Photographs; Introduction History; Impacts; Distribution

Myriophyllum spicatum
Integrated Taxonomic Information System.
Taxonomy

Eurasian Watermilfoil - Plant Invaders of Mid-Atlantic Natural Areas (2002)
DOI. National Park Service and Fish and Wildlife Service.
Identification/Description; Photographs; Distribution; Introduction History; Impacts; Controls

Whole-Lake Applications of Sonar for Selective Control of Eurasian Watermilfoil, Feb 2001, ERDC/EL TR-01-7 (PDF | 895 KB)
United States Army Corps of Engineers. Engineer Research and Development Center.
Controls; Research

Eurasian watermilfoil - Aquatic Plant Information System (APIS)
United States Army Corps of Engineers. Engineer Research and Development Center. Environmental Laboratory.
Identification/Description; Introduction History; Impacts; Habitat; Distribution; Dispersion; Controls

Myriophyllum spicatum L. (Eurasian Watermilfoil) - Noxious and Nuisance Plant Management Information System (PMIS)
United States Army Corps of Engineers. Engineer Research and Development Center. Environmental Laboratory.
Identification/Description; Photographs; Introduction History; Impacts; Distribution

Predicting the Invasion of Eurasian Watermilfoil into Northern Lakes, Technical Report A-99-2, Feb 1999 (PDF | 458 KB)
United States Army Corps of Engineers. Waterways Experiment Station.
Controls; Research

Foiling Watermilfoil (Mar 1999)
USDA. Agricultural Research Service.
Controls; Research

Myriophyllum spicatum Article Citation Search - AGRICOLA Database
USDA. National Agricultural Library.
Research; Special Note: NAL Catalog Search (resources)

Myriophyllum spicatum - Germplasm Resources Information Network (GRIN)
USDA. ARS. National Genetic Resources Program.
Taxonomy; Legal Aspects

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