Lawanda's Garden

You thought purple loosestrife was bad?  There’s a new biological bully taking over the marshland:  meet phragmites.

This gargantuan grass is so invasive that it’s rolled over other marsh invaders such as loosestrife, reed canary grass and non-native cattails like a steamroller.

You’ve seen phragmites.  It’s a big sturdy grass, up to 20 feet tall, with long strappy leaves and feathery plumes.  Kind of looks like a cornfield that has been planted too close together.  If you haven’t seen it in the marsh, you’ve seen it in ditches along major highways throughout Wisconsin.   Now it’s colonized wetlands, especially in the eastern half of the state.

Homeowners along Lake Michigan from Sheboygan to Door County have lost their lake views.  Duck hunters find it impossible to push their skiffs into the dense growth to hide their boats from the ducks.  Fishermen in inland lakes can’t get their boats away from their docks – if they can even find their docks – to get out to their favorite fishing spots.

Along with the inconvenience to humans, stands of phragmites become so dense that diverse natural wetland plant communities are entirely crowded out.   These invaders do not provide the food and shelter for fish, insects and wildlife that native plants like wild rice, bulrush, pickerel-weed and arrowhead do.

Phragmites is extremely flammable in fall, causing a danger of wildfires in marshy areas.  The tall, densely growing plants make it nearly impossible to fight any fire that starts.  A carelessly discarded cigarette or spark from a passing car could be disastrous.

The Wisconsin Department of Natural Resources has received nearly $806,000 in grants through the Great Lakes Restoration Initiative to pay for herbicide spraying on 3,600 acres along 118 miles of Lake Michigan shoreline.  The DNR sprays from helicopters where the grass is impenetrable.   Where there is access, they use boom or backpack sprayers and the bundle, cut and treat method (more about that later.)

What can you do if you have phragmites on your property but aren’t “lucky” enough to live in the area covered by the DNR grant?  There are several methods of control, especially if the stand is small.

• Try frequent mowing so the plants don’t get a chance to photosynthesize and send nutrition down to the roots.  Eventually they will die.
• Cover the plants with thick black plastic weighted down with rocks.  The plastic has to be heavy enough so the phragmites shoots can’t lift up or poke through the plastic.  The plastic will need to be in place for at least a year to kill the plants.
• Roots can be excavated to a depth of at least one foot.  This is very labor intensive and excavated roots must be buried at least four feet deep or sent to the landfill.
• Burning is successful only when used in combination with a chemical herbicide.  Herbicide application in fall followed by burning in spring seems to work best.
• Chemical herbicides labeled for use in aquatic areas such as Rodeo and Habitat can be applied.  Round-up is NOT labeled for aquatic use, so don’t even think about using it.  An area is considered aquatic if it is below the ordinary high water mark.  A DNR permit is needed to apply chemicals if the area is wet at the time of treatment.  It is considered wet if your socks would get damp if you stood there without shoes.

The bundle, cut and treat method is best for small stands and is best done in late summer or early fall before the stems turn brown.  Get some sisal twine, which will degrade in a year or so, and cut it into 14-inch lengths.  Gather a handful of neighboring green phragmites canes and tie them firmly with the twine at waist high or lower.  Cut the bundle with a sharp hedge shears just above the twine and immediately spray or paint the “stumps” with herbicide.  Apply just enough to moisten the fresh cut edges.

The cut vegetation can be left where it falls, except if there’s a chance it could float away.  Then it should be collected and placed in clear garbage bags and sent to the landfill.  If you think your garbage collector will balk at picking it up, label the bags “Invasive plants approved by the DNR for landfilling.”

If that all sounds like too much work,  if you have a large stand or if the whole shoreline of your lake is infested, get neighboring property owners together and contact a certified pesticide applicator.

About 90% of the phragmites will be killed with the first herbicide application, so follow-up is needed one year later to get the stragglers.

A small stand of phragmites will soon be a large one, so we need beat this bully back before it takes over our part of the world.