Curly Leaf Pondweed
Note the alternate leaf arrangement on the stem and the wavy and serrated edges.
Treating curly leaf pondweed near the shoreline
Curly Leaf spreads by the turions. (hard cone-like seeds)
Problems: Mats made navigation and fishing impossible in some areas of the lake. Wind broke plants and blew them to shore in big rolls. Residents collected them by raking them up and hauling them away. The plants made excellent mulch and fertilizer though! Millions of green and brown cone-like turions blew in to shore forming piles near shore and under docks.
Aquacides used were Aquathol K and Hydrothol 191 in low concentration at 55-60F water temperature before native plants have started growth, but during an active growth period of curly leaf before turion formation. In 2006 the aquacide Reward was used instead of Aquathol K and Hydrothol 191 as it proved to be more effective, particularly in near shore areas. Low concentrations of these chemicals according to extensive studies, are not harmful to fish, fish fry or any other aquatic creatures.
The aquacides were applied either by a sprayer or injected under the water surface.
Chemical treatment, at the present time, costs $300/acre + a $400 delineation or survey fee + a $750 DNR treatment permit, which is the maximum permit fee or "cap" charged for multiple parties on a lake.
2003 treatment: $15,200 for treating 55 acres of open water--Suggested contribution was $218.
2004 treatment: $6,370 for treating 20.5 acres of open water
2005 treatment: $13,350 for treating 45 acres of open water
2006 treatment: $11,950 for treating 36 acres of open water and 4 acres
2007 treatment: $9,150 for treating 30 acres of open water and near shore areas.
In 2007 the suggested contribution was $80 and all funds were used as more curly leaf came up than was expected.
2008 treatment: 40 acres were treated at a cost of $11,950. Suggested contribution was $185.
2009 treatment: 28.8 acres were treated at a cost of $9195.92. Suggested contribution was $120.
2010 treatment: 23.5 acres were treated at a cost of $7,597.40. Suggested contribution was $120.
2011 treatment: Only .69 acre of near shore CLP (near docks & boatlifts) was treated because CLP and native weeds came up at the same time due to the late, cool spring. The DNR would not allow open water treatment as too many native weeds would be destroyed by later treatment. CLP usually is the first plant up in the spring and treatment is done in 50-60F water temperatures in mid to late May, in order to protect native weeds that come up later in warmer water.
In 2011, the total cost of treatment was $949. ($750 DNR treatment permit + $199 for the chemical treatment) Suggested contribution was $80.
Total amount spent by the Portage Lake Association for CLP management over 9 years is $85,712.32.
From 2003 to 2011, the Portage Lake Association raised the funds themselves, by voluntary contributions. In 2003 the suggested contribution was $218. In 2011 it was $80. Between 65-70 contributions/year have been received in the past. We have made progress--from treating 55 acres of CLP in 2003, down to 23.5acres treated in 2010---with no large mats covering the water surface.
For 2012 CLP treatment, the estimated cost for 25 acres is $7,500 @ $300/acre + $750 DNR treatment permit (the maximum/lake) + $400 delineation or survey fee=$8,650 (total cost)
Suggested amount for each contributor is $50 as we have over $9,000 in the CLP savings account.
But----we don't have a good idea how much CLP could come up this spring, due to no open water treatment in 2011, and this amount could be totally used up if over 26-27 acres need treatment.
Because of this uncertainty, residents voted at our annual meeting last summer to contribute $50 per household so some money would be contributed each year so hopefully, we won't run short, and some money will be left in the account for future treatment.
Please write checks out to the Portage Lake Association and send to:
Marilyn Peterson, 12651 Far Portage Dr., Park Rapids, MN 56470 by April 1, 2012.
If you have Curly leaf in water close to shore-up to 100 feet out:
This is not covered by the open water permit. The lake association will pay for the near shore treatment if you sign a DNR permission to treat form. Forms were mailed out in Feb. 2012. Please understand that by allowing unhindered growth of curly leaf by your shoreline, you are providing a breeding ground for turion production that can affect the whole lake and increase the cost of open water treatment in the future.
If you have questions about curly leaf treatment or arranging native weed treatment, call Patrick Selter at PLM Lake and Land Management Corp.
Phone: toll free (866-687-5253) or e-mail: firstname.lastname@example.org
Please report areas of curly-leaf you might see, to Marilyn Peterson.
Click here to download curly leaf ID sheet
(pdf file-requires Adobe Acrobat Reader)
Almost everything you want to know about
Curly Leaf Pondweed
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Curly leaf Pondweed (Potamogeton crispus)
Curly leaf is an exotic (not native to the U.S) plant specie introduced from Europe in the early 1900's. It is a rooted, submerged aquatic plant that grows aggressively in 4-10 ft. of water. Though it loves light, it is an opportunist; it can tolerate low light and can grow under algae blooms or ice.
Curly leaf affects lakes in several ways, making it a very obnoxious aquatic exotic plant. The plants grow rapidly in early spring, reaching its peak in early summer crowding out native plants. Its dense floating mats interfere with swimming, fishing, boating and recreational enjoyment of lakes. As it decays in early July, it releases nutrients fueling excessive algae blooms and produces difficult dead plant disposal as wind and waves deposit plants on shorelines.
Its life cycle gives it a competitive advantage over many other aquatic plants. Curly leaf begins a rapid growth period when the ice melts and water temperature warms-so rapid a growth that it crowds out later germinating native plants. In later spring, flower spikes are produced that emerge above the water surface. By June, the fruits are mature on the stalks and drop to the sediment. The seeds in these fruits have very low germination rates. Prior to dying back in mid-summer, curly leaf produces large numbers of small buds, called turions in leaf axes along its stem. These turions are the primary way the plant reproduces. These hard cone-like turions are dispersed by water movement, sink to the lake bottom, and lie dormant during the summer. As water cools in the fall, the turions sprout to form new plants, which remain alive under the ice waiting to proliferate again immediately when the ice melts. Ice fishermen have found curly leaf growing up into their fishing holes. When there is very little snow cover, a lot of light filters through the ice, causing winter growth giving curly leaf plants a head start.
The unique life cycle also makes curly leaf difficult to manage. Strategies must include stopping turion production, reducing plant biomass, and depleting the seed bank in the sediment. The most effective management is accomplished with herbicide treatment in early spring when water temperature is 55-60F and before turions have been produced. Treatment is necessary for several years to control turions that may remain in the sediment and sprout.
Portage Lake Curly leaf History
Infestation: early to mid 90's -perhaps on someone's boat motor propeller, trailer or in the water intake of a jet ski-nobody knows for sure
First mats observed: 48 acres of ugly brown mats on the water surface during late spring and early summer of 2002
Curly leaf pondweed mats on Blueberry Lake between Park Rapids and Menahga in Wadena county
Close-up view of curly leaf mat on Portage Lake