Preventing Lake Weed Problems
Southern Ponds & Wildlife Vol. 3 #1 (Winter 2004)
Don C. Keller
Every spring during the months of April and May, I get hundreds of calls from pond owners who seem to be overwhelmed with vegetation problems. They usually state that they began fertilizing in March and had difficulty establishing a desirable plankton bloom (green color). What they fail to say is that there was some vegetation in the pond when they began fertilizing. The reason they couldn’t get a bloom was because the vegetation was sucking up the fertilizer.
All vegetation responds to fertilizer, sunlight and moisture. When you go to your pond in late February or early march to begin fertilizing, you should first walk around the pond perimeter and see if you observe any unwanted vegetation growing in the shallows. If you don’t see any, but you have had a problem in the past, I suggest you take your casting rod and tie on a weighted lure, cast out to the deep water, and drag it slowly across the bottom. If it comes back clean, go ahead and start fertilizing.
I have seen some lakes that did not have vegetation on the edges but would have rooted plants growing in 6-8 feet of water and were difficult to see from the shoreline. Once these lakes were fertilzeed, the vegetation seemed to explode and would soon top out at the surface. Weed treatment then becomes very expensive and may have to be handled by a professional.
If vegetation is observed, the first thing you should do is get a sample and have it identified. Place your sample in a zip lock bag and send it to a fisheries consultant. Once plat is identified, a chemical treatment can be recommended. Almost all herbicides are ineffective until the pond water reaches 55-60 degrees F.
I have often heard the statement from perplexed pond owners’ “I thought that if I fertilized, I wouldn’t have a moss problem.” Well, this is partially true. The main purpose of a fertilization program is to increase the food supply available for your fish. This is done by first creating a phytoplankton bloom, which imparts a green color to the water. This green color also creates a shading effect which blocks sunlight and prevents unwanted vegetation from developing if none were present when the fertilizing began.
Grass carp are a very useful tool but keep in mind that they are cold blooded and their body temperature will be the same as the pond water. Therefore they will eat much more when the water temperature warms up. If you wait for them to clean up the weeds, you may have to delay fertilization for several months, which will also slow the growth of you sport fish.
• Visit the pond and see if any vegetation is present.
• If vegetation is found have it identified and treatment recommended.
• Check water temperature and treat once the water warms to 55-60 degrees F.
• Add grass carp to prevent the problem from re-occurring.
• Begin fertilizing when the weeds are dead or disappeared.
• Remember, A stitch in time saves nine!
WEED CONTROL, 4 GOOD OPTIONS FOR BUR REED
Bur Reed, sparganium, is a flowering perennial weed that grows in the shallows of marshes, ponds and streams. There are 9 different species of Bur Reed in the United States.
Bur Reed has long, narrow alternating leaves that may be floating or emersed, erect or limp. It spreads from detached rhizomes and seed from spherical flower heads. Seed survival is not high.
Bur Reed does provide both food and habitat for nesting wildlife.
4 good options for control:
Endothall is a fast-acting contact option best applied early summer when submersed weeds are 12-14” tall and water temperature is 65°F or warmer. Repeat treatment may be needed to make good contact with all of the foliage.
Diquat is a second fast-acting contact option that can be applied any time good contact with the foliage can be made. Again, repeat treatment may be needed to make good contact with all of the foliage.
Glyphosate is an excellent mid-season systemic option. Application is best made when spherical flowers appear. Repeat treatment may be needed to kill the entire rhizome.
Rhizomes are easily uprooted. Dispose far from shoreline to prevent re-growth. Regular cutting will also reduce the amount of growth.
Cattle & livestock will eat Bur Reed. This is not a normal biological control option but it will significantly reduce the amount of growth. Grass Carp will also eat Bur Reed. It is not their first choice but they will consume it if there is nothing else available.
Reduction of sunlight and/or reduction of water level will both impact weed growth. Water level should be reduced to dry out for a period of 2-3 months.
Water Plantain (alisma) is a perennial herb, native to Eurasia and North Africa, now present world-wide.
Water Plantain grows in shallow marshy soil along the shoreline. It has stiff lance-shaped leaves 5-8” long that stand above the water surface. Emersed leaves have prominent parallel veins. Submersed leaves are smaller and ribbon-like with less defined veins. Water Plantain has small white 3-petaled flowers which whorl around a delicate stalk that open in the morning from June through August.
Water Plantain reproduces from seed and division of corms (a fleshy bulb-like underground stem).
Water Plantain is a food source for most waterfowl & fish.
When left unattended this vigorously growing weed can become a real problem and is considered a noxious weed in California rice fields.
3 Tips to eradicate Water Plantain are:
1) Early physical removal by grabbing the main stem at center and pulling upward. Make sure to get the entire corm and root.
2) Use 2,4-D systemic herbicide for early spring control. Apply as new growth begins to appear. Repeat treatment 3-5 weeks after the first application if weeds begin to show signs of recovery.
3) Use glyphosate systemic herbicide for mid-season control. Apply when 50% or more foliage is above the water surface and weeds are in full bloom. Repeat treatment 3-5 weeks after the first application if weeds begin to show signs of recovery.
Water Buttercup, Water Crowfoot (ranunculus aquatilis), is one perennial weed in the Buttercup family that has 360 different species. It can be found world-wide in the quiet waters of ponds, in ditches and along the shoreline of lakes and slow moving streams.
Water Buttercup is eaten by a variety of waterfowl and fish. It also provides habitat for aquatic insects.
It has 2 distinct types of leaves. Submersed leaves are alternately attached, fan-shaped with fine thread-like leaves that collapse when removed from the water. Floating leaves, when present, are flat and have 3-5 scalloped lobes. It has a single flower on a stiff stalk that rises above the water surface. The flower has a yellow center and 5 white petals that bloom from April to August.
Water Buttercup propagates from seeds and stem fragments.
Water Buttercup can grow in thick dense mats that will restrict water recreation including boating, swimming and fishing.
Physical removal and chemical treatment are 2 good options.
1) Physical removal can be easily obtained by cutting or raking out all the weed fragments.
2) Chemically control area with diquat.
Diquat mixed with a non-ionic surfactant is an excellent fast-acting contact option. Addition of copper ethanolamine will often improve effectiveness in difficult to control areas.
We recommend, 30 oz. of WEEDTRINE-D Liquid with 3 oz. CYGNET PLUS Liquid or combine 18 oz. of WEEDTRINE-D Liquid, 4 oz. of CUTRINE-PLUS Liquid and 3 oz. of CYGNET PLUS Liquid. Add enough water to the concentrate to make 1½ gallons of spray solution. 1½ gallons of solution will treat 1,000 sq. ft. (100’ x 10’). It is best to treat before flowering. Repeat treatment may be needed to make good contact with all the foliage.
A customer recently contacted us regarding Horsetail control. Below is his question and our response.
We have lots of “Pipe Cleaner” grass also known as Horsetail. It is in the water and around our burm & beach area. They are long green stems with brown rings about every 6-8 inches around. They are hollow and I have never seen any flowers or leaves on them. They are taking over our 1 acre pond. Do you have any products or recommendations for getting rid of it? Thanks!
Horsetail is one of the few plants that has survived since the dinosaurs! As you may already know, Horsetail is easy to identify but difficult to control.
Aqua Neat/Shore-Klear Liquid has moderate affect on Horsetail. Aqua Neat/Shore-Klear Liquid is systemic and should kill the entire root system.
For best results mix 26 oz. Aqua Neat/Shore-Klear Liquid with enough water to make 1 gallon of solution and top with 2 oz. Cygnet Plus Liquid and spray over weeds late spring when they look like small bare pine trees. The stems contain large amounts of silica, slightly bruise or crush the stems prior to application to achieve better penetration. Repeat treatment may be needed to kill the entire root system.
Aqua Neat/Shore-Klear can also be injected into Horsetail early spring by cutting the cone-like top and injecting solution directly into hollow stem. This option is labor intense but can be very successful. Repeat treatment will be needed annually for 2-3 years.
A second option is manual removal, by cutting and destroying stems before spores develop. Persistent removal of the cone-like tops about 3 weeks after they emerge should provide good control. Annual removal for 3-4 years may be needed.
What is a Phragmite? Though it sounds like an exotic insect or rare incurable disease, Phragmite, is commonly known as Reed Grass. Invasive Phragmites arrived in the 1800s from ballast on ships that arrived from Europe. This ballast contained sediment and seeds or rhizome fragments that were frequently dumped along the shoreline.
Phragmite is a large, coarse perennial grass that can grow up to 15 feet tall. The leaves are 2-2.5 inches wide and 8-15 inches long that alternate on the stem. Phragmites have a distinctive seed head with feathery plumes at the stalk end which appear mid-summer and last all winter long.
Phragmite spreads rapidly from seed and rhizomes. Mature rhizomes can extend 6 feet below ground making physical removal difficult. New plants grow rapidly from rhizome fragments and also from seed. Each mature plant will produce up to 2,000 seeds each year.
Native Phragmite provide habitat for birds, water fowl, mammals and fish. The invasive species has such dense, stiff shoots it competes with native vegetation and stops all wildlife but a few insects from habitation. The invasive species also limits access to lakes, rivers and recreational areas.
Native Phragmite has low stem density. Stem is reddish-purple in spring changing to chestnut brown in the fall. Stems are flexible and bend easily in the wind. They are smooth with a polished shiny appearance and normally grow crooked. Leaves drop off easily in fall. Rhizomes have a round shape and are yellow in color.
Invasive Phragmite has high stem density. Stem is tan through both spring and fall. Stems are sturdy, erect and do not bend easily in the wind. They are dull with a rough, ribbed appearance that always grow perfectly straight. Leaves are very difficult to remove. Rhizomes have a flattened shape and are white or light yellow in color.
Native and invasive Phragmite are both controlled with the same chemical and physical options. There are no known biological options to date.
Glyphosate is a systemic herbicide that will kill the entire weed, root and all. Glyphosate is virtually non toxic to mammals, birds and fish. For best results, apply to actively growing weeds mid-summer when growth is in full bloom. Including a liquid non-ionic surfactant will help the herbicide stick to the foliage and penetrate into the weed more readily.
Physical control is best accomplished by repeatedly cutting stems in early spring when weeds are only 12 inches high. This will shock the weed and reduce new re-growth. Do not cut for a minimum of 2 weeks after chemical treatment.
Phragmite often will recover 3 years after chemical treatment. Retreatment may be needed if weeds show signs of recovery.
A customer recently contacted us regarding Cattail control. Below is his question and our response.
I have about a ¼ acre pond with an average depth of 4 feet and a significant amount of cattails. The pond was established about 13 years ago and has a significant population of fish: mostly bass and blue gill. Each year I have “gloved-up” and dug through the mud to pull up the root systems, but this past year I skipped and the weeds are winning! Do you have a product that will target the Cattails without destroying all the other plants (that frogs and young fish in the mature) and won’t harm the existing population of fish also with 2 large dogs that are in the pond daily throughout the year until it freezes? Please let me know. Thank you.
There are 2 basic types of Cattail, Common and Narrowleaf. Common Cattails leaves are ½” or wider with no space between the 2-part spike. Narrowleaf Cattail leaves are less than ½” wide and have a space between the 2-part spike. Both types reproduce from tubers and seed. If the entire tuber is not removed, the portion left behind will send up new growth. As the brown spike matures in the Fall it releases seeds that drop, root and sprout new weeds.
2 good options for Cattail control are:
Aquacide Pellets are a systemic option for Common Cattails. See attached photograph. For best results, apply early spring to new growth as it begins to rise above the water surface. Apply at the rate of 10 lbs. per 2,500 sq. ft. (50’ x 50’).
Shore-Klear Liquid is a systemic option for both Common and Narrowleaf Cattail. For best results, apply mid-season when Cattails are up and in full bloom. Mix 2 oz. Shore-Klear Liquid with enough water to make 1 gallon of solution and spray over foliage on a warm sunny day. A 2,500 sq. ft. area would require approximately 5 oz. Shore-Klear Liquid per treatment.
Cattails are very aggressive weeds. Repeat treatment may be needed 3-5 weeks after the first application if weeds begin to show signs of recovery.
When applied according to label directions, neither product will harm frogs or fish. Dogs can swim and cattle can water the same day as application.
Crested Floating Heart is native to Asia, introduced to the U.S. through aquatic plant nurseries that still market these plants today. It escaped from cultivation in the 1990’s and has been an aquatic nuisance established in public waterways in Florida for years. Today, Crested Floating Heart is scattered abundantly throughout many southern states with tropical climates.
Crested Floating Heart has heart-shaped floating leaves at the ends of long stems that are rooted in submersed sediment. It has slender, tapered clusters of tuberous roots on the underside of it's floating leaves and features a small white 5-petaled flower. These weeds propagate from tubers (“ramets”) or daughter plants that break free from it's mother. This small fragment can be transported by wind, flowing water, boats, boat trailers and re-establish as new colonies. Crested Floating Heart can out-compete native plants, impact water supplies from hydropower plants, disrupt the ecosystem, and ruin recreational activities such as boating, swimming and fishing.
There are no known insects that feed on Crested Floating Heart. Grass Carp (weed-eating fish) will not eat it, winter draw down does not work and mechanical removal is ineffective. Aggressive chemical control is the best way to remove new colonies of Crested Floating Heart. 2,4-D is a systemic option that is best applied at 2ppm early spring at the first sign of new growth. Repeat treatment 3-5 weeks after the first application if weeds begin to show signs of recovery. Glyphosate, mixed with a surfactant, is most effective mid-season when leaves are up and in full bloom. Repeat treatment will be needed to kill the entire root system. Endothall is a fast-acting contact option that can be applied anytime good contact with foliage can be made. For best results, apply at the highest recommended rate of 5ppm. Repeat treatment will be needed approximately 45 days after the first application or when good contact with foliage can be made.
It is important to do our part. Buy native plants for backyard water gardens. Remove known invasive weeds from our ponds so they don’t invade neighboring waterways. Clean boats and boat trailers carefully when removed from infested waters. Finally, report Crested Floating Heart sightings to your local environmental agency.
Curly Leaf Pondweed is a perennial weed that is native to Europe. It escaped into American waters in the late 19th century and was first noticed in Minnesota in 1910. Curly Leaf Pondweed was found in most of the United States by 1950. It gets its name from the oblong rippled (curly) submersed leaves. Leaves are serrated and alternately placed, typically 3” long with a reddish mid-vein. It has annual burr-like winter buds (turions) and small reddish-brown fruit.
Curly Leaf Pondweed has a unique life cycle. In early spring, Curly Leaf Pondweed is one of the first weeds to appear and will die back by mid-July. Turions begin forming early summer and continue to germinate in the fall. These turions remain alive even in winter under thick ice.
Curly Leaf Pondweed grows rapidly. This rapid growth may crowd native growth and reduce recreational activities like fishing, swimming and boating. These limitations may also reduce real estate values.
4 control methods:
Hand pulling is intensive and time consuming. Cutting at the base can prevent turion production. Weeds will re-root from fragmentation, so removal of all fragments is necessary.
Grass carp will consume Curly Leaf Pondweed. Recommended stocking rates are 7-15 fish per surface acre. Results seldom appear until the second season.
Diquat, endothal and fluridone are three good control options, especially when applied early, prior to production of turions. Diquat and endothal are both fast-acting contact options that will quickly kill the foliage they touch. Both options can be used for spot treatment or treatment of the entire pond. Fluridone is a systemic option that will kill the entire weed root and all. This option is best applied early spring to new growth. It must be applied to the entire pond and is not recommended for spot treatment.
This is an effective option for small areas including swimming beaches and around docks.
5) Barriers will block sunlight that weeds need to grow. This option will have to be anchored and routinely maintained and may have a negative impact on trapped organisms below the barrier.
Prevention is an ideal way to prevent spread of Curly Leaf Pondweed. Be sure to clean your boat and trailer of any weed growth before launching or removing your boat from any water body.
A customer recently contacted us regarding lake weed control. Below is her question and our response.
I have property on Lay Lake (Coosa River) in Alabama. As you will see in the picture attached. I have a huge problem with weed growth along my shore line. I would appreciate you identifying them and offering a suggestion for product usage to destroy and prevent future growth. Thank- you for your assistance in the matter.
Your photo appears to be Water Primrose.
Aquacide Pellets are an excellent systemic option that is best applied early spring as new growth begins to appear. Apply at the rate of 8-10 lbs. per 2,500 sq. ft. (50' x 50'). Repeat treatment 3-5 weeks after the first application if weeds begin to show signs of recovery.
Shore-Klear Liquid is an excellent systemic option best applied mid-season when foliage is above water surface and the weeds are in full bloom. 5 oz. of Shore-Klear Liquid mixed with 2.5 gallons of water and topped with 3 oz. of Cygnet Plus Liquid will treat 2,500 sq. ft. Again, repeat treatment may be needed to kill the entire root system.