March 13, 2015
Contact: Jerry Grundtner, jagrundtner@msn.com 612-751-4666
Flowering Rush – Invasive species in Forest Lake
Informational /Open House Meeting
Meeting to be held on April 8 at Forest Lake City Center
Forest Lake has recently become infested with an aggressive aquatic invasive species (AIS) called
Flowering Rush, sometimes mistakenly called onion grass. Dense stands of flowering rush may interfere
with swimming and other recreational uses of the lake, and also choke out native vegetation. Flowering
rush is currently only in 2nd and 3rd lakes and has not yet been detected in 1st lake. However, its spread
is imminent and it is only a matter of time until 1st lake becomes infested. In 2014, the FLLA, in
conjunction with the CLFLWD and the City of Forest Lake, determined that an effort needed to begin in
order to rid Forest Lake of this invasive species.
The Forest Lake Lake Association (FLLA), in conjunction with the Comfort Lake Forest Lake Watershed
District (CLFLWD) and the City of Forest Lake, is holding a public informational /open house meeting to
educate citizens and explain the planned treatment of Flowering Rush in Forest Lake during the summer
of 2015. The Informational /Open House will be held on Wednesday, April 8, 2015 from 6:30 to
8:00p.m. in the Forest Lake City Center (1408 Lake Street South). This meeting is open to all residents
of Forest Lake and homeowners who live on Forest Lake. Refreshments and light snacks will be
provided.
Jerry Grundtner, a member of the FLLA Board of Directors, said that “all entities are committed to begin
the process of removing this invasive species from Forest Lake before it reaches an uncontrollable
presence, and to prevent flowering rush from spreading into other water bodies in Washington County
and the State of Minnesota.”
The informational meeting will begin at 6:30 p.m. and from 6:40-7:45p.m., several guest speakers,
including Blue Water Science, representatives from the FLLA, CLFLWD and the City of Forest Lake, will be
present to share information on what flowering rush is, the planned herbicide treatments and manual
cutting that are scheduled to begin in July 2015, and will be able to answer any additional questions. The
hope is that Flowering Rush can be eradicated to allow Forest Lake to remain one of the premier lakes in
the region.
We hope to see many of you at the open house. RSVP is preferred but not required.
To RSVP: http://tinyurl.com/ForestLakeFloweringRush
History of Flowering Rush on Forest Lake
AIS are organisms that have been introduced, or moved by human activities, to a location where they do
not naturally occur. Due to a lack of predators in new environments, AIS populations may grow
exponentially and choke out native vegetation. Flowering rush has been in Forest Lake for the last 7-8
years and is steadily spreading. Currently, Forest Lake does not have Zebra Mussels, Eurasian Milfoil, or
other aquatic invasive species found in Minnesota lakes.
It is not certain how it was transported to Forest Lake, but flowering rush is extremely invasive and
spreads in two ways: from the seeds dropping from its purple flowers on top of the rushes and from the
Rhizomes, which are underground stems. The rhizomes are attached to the root system and come loose
when the plants are pulled. Water currents, ice movement, muskrats and geese can easily move these
reproductive structures to new locations in the lake.
In July of 2014 Blue Water Science performed the initial delineation of the Flowering Rush sites on 2nd
lake and provided markings and GPS locations of affected sites. On September 9, 2014, the CLFLWD
contracted with PLM, an aquatic herbicide treatment firm out of Detroit Lakes, to apply herbicide to
flowering rush identified on 2nd lake. On October 8, 2014 Blue Water Science went back onto 2nd lake to
assess the results of the herbicide treatment.
From their assessment, it appeared that the application had eliminated some of the targeted flowering
rush but not all. It is important to remember that in all discussions regarding flowering rush that it was
always explained that this would be a 2 -3 year process and that it would take multiple applications of
herbicide with the goal of eventually killing it completely.
Blue Water Science also performed a flowering rush delineation on 3rd Lake on October 8, 2014. From
the delineations in July and October it has been determined that 2nd Lake currently has about 34 sites of
flowering rush ranging in size from 10 square feet (SF) to 1000 SF and 3rd lake has 135 sites from 10 SF to
over 50,000 SF (over 1 acre). This equates to over 340,000 SF (approximately 8 Acres) of flowering rush
identified. It appears that it is more invasive than thought and is spreading more each year.
This is a multiyear effort and will require the cooperation of all organizations and the homeowners who
live on the lake. Maps below show the extent and the locations of the flowering rush that were
identified in the delineations completed in 2014.
Sincerely,
Forest Lake Lake Association www.ourforestlake.com
Comfort Lake - Forest Lake Watershed District www.clflwd.org
City of Forest Lake www.ci.forest-lake.mn.us