Our creeks, marshes, and ponds lie surrounded by thick stands of reeds.
Reeds are a very large, very tough, very long lived grass. Found in temperate and tropical wetlands across much of the planet, they have their uses.
But like any grass, they grow from extensive mats of roots and rhizomes, creeping along in the mud.
Some of our reeds are native plants.
Known as Phragmites australis, subspecies americanus; the native reeds grow across our entire continent from southern Canada south to the Mexico border in the west.
Here on the east coast, they grow as far south as our border with North Carolina.
Another species, possibly native, grows along the Gulf coast. Phragmites australis subspecies berlandieri may have crept northward from Central and South America at some point. It has now moved westward and is found in parts of Arizona and California. Items made from reeds, found in archeological digs in the American Southwest, date to over 40,000 years old.
Our native species co-exist with other marsh and aquatic plants. They were used by Native Americans for food, shelter, and to make useful things. Every part of the plant is edible. Spring shoots may be harvested and eaten like bamboo shoots.
But another, hardier species of reed, Phragmites australis, was brought to North America by European ships in the 18th and 19th centuries. Like so many “exotic” species, it has become invasive, choking out other species which at one time grew along our waterways.
Phragmites australis grow across much of Europe, North Africa, and the Middle East. They are an ancient species. In their own native areas, they aren’t invasive. And they have been used for many purposes for thousands of years. But transplanted to North American waters, they behave differently.
Why should we care about which reeds grow along the creeks and in the marshes?
It all comes down to biodiversity.
When lots of different types of plants grow together in a community, many types of animals find food and shelter. A greater number of species can live together in harmony in a place. Their relationships are rich and complex. The whole community becomes stronger and better able to withstand fluctuations in climate. The ecosystem remains in balance.
When an invasive species gets a foothold, it often grows stronger and faster than the native species it replaces. It has fewer animals which use it. Soon the invasive species takes over, creating a monoculture, spreading, and changing the community so that fewer species can live in that place.
And that is exactly what is happening to our waterways across much of the United States.
The area where we live, around the Chesapeake Bay, is one of the few areas in North America where the native species of reed still lives. And the natives are crowded out, more each year, by the invasive Eurasian reeds.
Now, these reeds, known as Phragmites (pronouced “frag-mahy-teez“), gobble up real estate along waterways. They can grow to over 15” tall.
Like bamboo, their system of underground roots and rhizomes grow many feet each year away from the clump, to cover new territory. These roots and rhizomes grow many feet deep below the surface.
At the surface, stolons, or horizontal stems, grow many feet each year. New plants emerge at each joint in the stolon, and each of these new plants sends down new roots. The result is a very dense, thick mat of growth at and below the surface.
Thick, dense vertical growth of the actual grasses grow anew each spring. They are so dense and so tall that they shade out any other plant which tries to grow in their midst. The stems of each plant are hollow. Large leaves grow at nodes along the length of the stem, much like the leaves on a stalk of corn. The plant is crowned with a very large plume of flowers, which produce thousands of seeds each season.
It is easy to see why these Phragmites spread so quickly! They not only spread out with their rhizomes and stolons each year; but those seeds travel by air and water to colonize new areas. Very few species of birds use the seeds. Very few species of animals make their homes among the Phragmites in a marsh. And currently, we aren’t harvesting and using these reeds in any substantial way.
Phragmites die back each winter, but are perennial and re-emerge each spring. The previous year’s stalks stand all winter long. Silt accumulates around them, and the water becomes progressively shallower each year. They eventually form a wall between the shoreline and the water, blocking the view and creating a dense barrier for anyone trying to access the water for fishing or boating.
Invasive Phragmites emerge early in the spring, before the native species and before many other aquatic plants. They grow taller and with more vigor than our native Phragmites australis, subspecies americanus.
They have grown into a hot topic of debate among those of us who live along the waterways they choke.
Many would like to get rid of them. But from what you now know about Phragmites, you probably understand why this is difficult and expensive. Their extensive root system allows them to regenerate after harvesting or burning. They must be burned for several years in succession to eventually destroy the roots.
There is experimentation with herbicides. But how will broadcast herbicides affect the birds, fish, amphibians, reptiles, and other plants living in marshes and shallow creeks? Herbicides are a controversial solution. Permits are required, and the herbicide must be sprayed during the period of active growth in late summer or early fall. The sprayed herbicides will travel, like the Phragmites’s seeds, in the air and water for many miles.
And who will pay for the herbicide, even if a community decides to go that route?
This is one of those slowly creeping problems which eludes an easy fix.
But Phragmites, though invasive, remain a useful plant.
They are sometimes planted to filter and clean waste water. They help catch run-off, trap harmful chemicals in their biomass, and remove other waste products so the water can be used again.
Phragmites also filter our air. They filter excess carbon from the air, using it to grow. Carbon, a major greenhouse gas, is removed from the air and returned to the soil through their efforts. While filtering carbon, they also remove other polluting gasses from the air we breathe, releasing pure oxygen and water vapor.
Phragmites stop erosion. Because they grow in any moist soil, they can hold areas which might otherwise erode from run off , tides, and flooding. They can tolerate brackish, salty, or fresh water. Tidal flooding doesn’t bother them.
These are wonderful plants with many uses and benefits. We don’t value them because we no longer need them as a natural resource for making things. We no longer eat them as a staple of our diet.
As with so many things, it is our own point of view which defines “nuisance” as opposed to “resource.”
Perhaps the solution to our problem can lie more in creativity and less in destruction of the growing world around us.
Words and Photos by Woodland Gnome 2014
For More Information:
Phragmites Field Guide
Invasive Species of the Chesapeake Bay
Guide to the Control of Phragmites, Maryland Department of Natural Resources