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GLA Working to Eliminate Yellow Iris

Education, News September 17, 2020 No Response

At left, yellow iris sites on Fisher Lake.

The invasive species yellow iris has spread in the watershed over the past several seasons and the GLA is asking riparians for their help in eradicating the plants. Property owners have been notified and are part of the solution to combat the spread. A group of nine NMC Freshwater Studies Program students are currently working with our GLA interns, assisting with identification, mapping and removal.

The work is focusing on the Fisher Lakes, but plants also can be found on the north and east shores of Big Glen and along the Crystal River. The removal project this season is expected to continue through the first week of October.


Native to Europe, Northern Asia, the Middle East and northern Africa, the yellow iris (Iris pseudacorus) most likely made it’s way to our shores as an ornamental plant. Many landscapers, pond designers and home gardeners choose to include it in their designs for it’s beautiful yellow flowers in bloom from mid June to mid July. It is lovely, in bloom, but problems arise when the seed pods mature, arch over the water, split open and disperse. It can travel far and wide on the waters of our lake, washing into crevices, lodging against berms and taking root. Over time it can create a dense mass, choking out the diversity of native plants that keeps our shores looking like northern Michigan and that keep our local ecosystem healthy.


Observed increasing over last several years by our watershed scientist Rob Karner and invasive plant specialist Laurel Voran. Laurel has been aware of this plant’s agressive nature from her work in the horticultural field and from the experiences of others in our region and nationwide. One person who has been involved with controlling this plant around Portage Lake described his experience like a game of “whack-a-mole” : “At first there were just a few, and then we found it popping up here, there and everywhere!”



This year we have taken efforts to carefully identify and document where yellow iris has taken root. We have done surveys by boat, by foot and by drone to assist in documenting as many current infestation sites as possible using mapping software.

We have removed the seed pods of any plants that flowered this summer to prevent further spread via water currents. (the seedpod stems arch down and can release into the water – spreading far and wide.)

Small infestations have been removed by digging. We are in the process of contacting affected landowners and determining best methods to destroy larger populations.

What you can do:

  • 1: Contact us immediately if you know you have yellow iris and have not already heard from us. Remove any existing seed pods, or give us permission to do so.
  • 2: Pay attention to any iris on your shoreline and let us know if any have yellow blooms next summer.
  • 3: Ideally: Work with us in removing any yellow iris from your shoreline. Minimally: remove and destroy seedpods from yellow iris plants you desire to keep.
  • 4: Do not purchase any yellow iris to plant anywhere on your property. (And- Be aware that yellow iris and our native blue blooming iris (Iris virginica and/or Iris versicolor) are confused in the trade. You may intend to purchase either of the natives, but it may reveal itself to be the yellow iris upon bloom.)
  • 5: If you find this Iris for sale at nurseries or garden centers, ask them to stop selling it.
  • 6: Donate to the GLA to support terrestrial invasive species efforts to help us cover the costs of erradicating it.
  • 7: Educate your friends and neighbors about the threats of this plants, in spite of it’s beauty.

Learn more by watching these informative videos on the subject.

Eradicating Yellow Iris and Purple Loostrife

Digging Out Yellow Iris

Understanding Overlay Districts

Education, News September 3, 2020 No Response

Steep slopes map

Every watershed should have a variety of tools to protect the water. Education is one of the biggest and most effective tools but effective zoning can pay big dividends as well.

Using a zoning Overlay District (OD), as defined by the boundaries of the Glen Lake/ Crystal River Watershed, is an excellent way to plan for the long-term protection of our water. If the OD does its job, it will be the gift that keeps on giving.

Keep in mind that existing development within the OD would be exempt from the new provisions. The OD would however provide guidance for future development and changes to existing development. Either way, every watershed resident should become educated on the OD to understand its implication for water protection within the context of reasonable development.

Click here to learn more about the “Overlay District” on the GLA website.

Glen Lake Association Celebrates 75 years, Rob Karner Recognized for 40 Years of Service

Education, News August 17, 2020 No Response

Clear skies and the 80-degree temperatures of a perfect summer afternoon didn’t keep more than 100 people from turning out for the GLA Annual meeting this August. The commitment of this organization’s members has not waivered for more than 75 years now.

Meeting participants were treated to two special videos; the first highlighting the history of the GLA, current programs and a vision for its future, (watch it here); and the second congratulatory messages from longtime community partners in watershed protection (see who they are). Additional acknowledgements from Senators Stabenow and Peters and State Senator VanderWall, State Representative O’Malley, Lt. Governor Gilchrist and Gov. Gretchen Whitmer were also shared, thanking the GLA for 75 years of service to Leelanau County.

Another historic milestone recognized during the meeting and acknowledged by elected officials was 40 years of service by Watershed Scientist, Rob Karner. Since 1979 Rob has built an outstanding curriculum vitae of science-based initiatives that have vaulted the association to recognition as one of the premier lake organizations in the Midwest … and one closely followed and often imitated by groups countrywide.

The many contributions of tireless volunteers and generous donors were also acknowledged including special thanks to the Greg and Sue Besio family. Their $100,000 gift to the popular Discovery Boat Program will help ensure this popular educational program created by Rob Karner will continue into the future. The Discovery Boat Cruises virtual or live are one of the best opportunities for the GLA to educate and share critical preservation information. They are just one more example of Rob’s relentless desire to share his knowledge with so many.

The State of the Watershed address by Rob Karner was comprehensive as always and generated great questions. A few highlights include the Watershed Protection Plan Update, a proposed Watershed Protection Overlay District and Swimmer’s Itch prevention. Slides from Rob’s presentation can be viewed here; video coming soon!

The business portion of the meeting included a solid finance report from outgoing treasurer David Herr (read it here). All three outgoing board members, Dale DeJager, Bill Witler and David Herr were thanked for the donation of their time for their wise counsel during their time on the board. Numbers from elections included 178 votes cast online and 15 proxy votes received resulting in election of all three highly qualified board candidates. Dave Cheney, Kris Fishman and Jennifer St Julian were welcomed onboard.

A message of thanks was delivered to outgoing president Dave Hayes, the GLA “won the trifecta” under his leadership by completing the first ever GLA Strategic Plan, implementing a new communication software, and adapting staff roles to better poise the GLA to meet the organizational and educational challenges ahead. A final message of gratitude for all our volunteers and encouragement to get involved was shared by Dave. Check out the full recording here.