Delaware’s marshy areas are full of them: Dark green reeds that can grow tall enough to dwarf a human. You’ve doubtless seen them, even if you took no note of them.

These are phragmites, a wetlands-based plant also known as the common reed or, more formally, as phragmites australis. The species grows up and down the state, though it is primarily concentrated near the coast.

It may seem to fit right in marshes, and indeed, there is a strain native to the area, but most of the phragmites in the state are invasive. As such, they threaten to disrupt native habitats, leeching nutrients away from long-established plant species that many local animals rely on.

According to the Delaware Department of Natural Resources and Environmental Control, phragmites have reduced native plant, fish and wildlife diversity along waterways like the Delaware Bay and Delaware River.

“Phragmites when left unchecked will completely take over a marsh,” said Jamie Joachimowski, an impoundment/habitat biologist who runs the phragmites program within DNREC’s Division of Fish and Wildlife.

Invasive species, by definition, outcompete native variants, disrupting ecosystems in the process. Many animals that used phragmites for food or nesting have been adversely impacted by the spread of the invasive species, which tends to grow taller and in more densely packed clusters.

“The non-native is pushing out the native species because it’s so darn aggressive,” said DNREC botanist Bill McAvoy.

The invasive strain is believed to have been introduced from Europe to the United States in the early 19^th century after it was used as packing material. It was first identified in the Philadelphia area and, by the 1840s, had made its way to Delaware, McAvoy said.

Today, the native phragmites is much rarer here than its foreign counterpart. The non-native species grows in both fresh and salt water, whereas the native variant prefers less salty water. In addition to the height and how densely packed together the plants are, an observer can tell the strains apart by the color and texture, with the invasive variety being a darker green and possessing a rough, ridged stem.

The native species can still be found in all three counties, such as along the Appoquinimink, Murderkill and Broadkill rivers but is significantly less common, as the invasive “will form monocultures where nothing else grows at all,” McAvoy noted.

It’s for that reason the state has actively been working to control the reed since the 1940s, with the General Assembly declaring it a nuisance plant in 1984. Fortunately, DNREC has developed one of the best phragmites control programs in the country.

For the past 40 years, DNREC has offered a cost sharing program to fund the removal of phragmites around the state. More recently, DNREC has partnered with the U.S Department of Agriculture’s Natural Resources Conservation Service to run an initiative known as the Delaware Phragmites Control Cost-Share Program. This program benefits Delawareans by treating phragmites both on public lands like wildlife areas and on private property at the owner’s request, with the landowner and government splitting the cost.

DNREC focuses on habitat restoration, aiming to manage the phragmites population and thus allow other flora — and, subsequently, fauna — to thrive in wetlands.

Joachimowski, who until recently was the program’s sole employee, is responsible for overseeing phragmites control throughout the state. Using herbicide, he arranges for sprayings to occur when and where they are needed. Generally, large patches on public lands are sprayed every few years to keep the plant in check.

Joachimowski keeps in touch with overseers of wildlife areas and related properties throughout the state so he can stay abreast of where phragmites are growing in large quantities. The goal is to treat about 3,000 acres a year between state and private properties.

Sprayings actually only take place during a fairly narrow window, from about August to October. Phragmites begins flowering in June, meaning efforts to eliminate members of the species with chemicals before then will not reach into the plant’s root system and simply lead to it growing back the following year.

DNREC typically uses the chemical glyphosate, occasionally turning to imazapyr when something more powerful is thought to be needed. The Department must be cautious about using imazapyr near other plants, though, as it can prove toxic to beneficial foliage like trees. As a result, DNREC will shy away from utilizing imazapyr in most cases, only applying it if there’s sufficient space between phragmites and other plants.

The herbicide is usually applied from a helicopter hovering roughly 30 feet above the ground. The sprayers, contractors hired from the same company that also handles mosquito control, are able to cover within a matter of minutes areas that would take a person on foot days to manually spray.

For areas of less than a quarter acre, as well as touch-ups after a helicopter visit, Joachimowski will go out and spray up close from his truck-mounted unit.

Most of the work takes place in the morning, as that’s when winds tend to be calmer.

Once sprayed, phragmites in an area will typically be kept in check for a few years, at which point another helicopter flyover might be arranged to kill off new growth. A 50-acre marsh that is sprayed one year might receive another dousing on a 10-acre portion the following year to ensure some particularly stubborn or otherwise missed phragmites remain under control.

“It’s not really a necessity to spray every bit every year. We’re trying to continuously work on it every year to keep it under control to keep it from reverting back to 100% phragmites cover,” Joachimowski said.

The plant is particularly prominent in eastern New Castle County, around Cedar Swamp Wildlife Area just a few miles north of the Kent County line (which is where the Delaware Bay turns into the Delaware River).

Of the 3,000 or so acres DNREC sprays each year, about a third to half are on private land. Property owners can apply to have the state spray their land as part of the Delaware Phragmites Control Cost-Share Program. As the name implies, the government picks up a portion of the cost.

Because of the paperwork involved, DNREC recommends landowners start the application process a year in advance. With spraying only occurring about two months out of the year, property owners are sometimes left waiting due to not completing the paperwork in time. Depending on available state funding, Joachimowski has the ability to offer financial assistance directly to Delawareans to cover that initial one-year gap.

Once enrolled, a property will receive spraying for three consecutive years. Delawareans must have between five and 200 acres of phragmites to qualify, and such lands must be accessible to aerial treatment. Tax ditches — subdivisions formed by landowners through a specific legal process in state court to oversee drainage of designated watershed areas — are not eligible for the program.

Joachimowski sprayed more than 60 parcels between public and private lands in 2024.

While landowners will sometimes contact DNREC about having phragmites removed for aesthetics reasons, the agency is concentrated on habitat restoration. In such a situation, Joachimowski will suggest the landowner reach out to a private company or handle the work themselves. DNREC does offer some do-it-yourself phragmites control tips, available at https://dnrec.delaware.gov/fish-wildlife/conservation/diy-phragmites-control/.

While phragmites disrupts habitats, it also can play a role in erosion protection, and so Joachimowski will direct the helicopter pilot to leave certain coastal areas alone to allow the species to strengthen dykes and levees.

Though the plant is a nuisance, it’s not the most problematic species of invasive plant here. Still, DNREC has the ability to control it and will continue working to manage the phragmites population. By doing so, Delaware is preserving the delicate balance of its marshlands, ensuring that native species can thrive for generations to come.

Related Topics:  fish and wildlife, habitat, invasive species, marshlands, nature, outdoor delaware, phragmites, plants