Naval Air Station Patuxent River Sericea Lespedeza Control

at Fishing Point

NMFWA Invasive Species Working GroupMarch 2014

Jacqueline Smith & James SwiftCIV NAVFAC Washington, Environmental Dept.

jacqueline.c.smith@navy.milJames.swift@navy.mil

Fishing Point Restoration

The Fishing Point Landfill is a 65-acre site overlooking the Patuxent River that was used for liquid and solid waste disposal from 1960 to 1974.

Remedial action was completed in 2007.

A native grass mixture was planted in 2008.

The seed mixture consisted of:• Switchgrass (Panicum virgatum)• Big bluestem (Andropogon gerardii)• Little bluestem (Schizachyrium scoparium) • Indiangrass (Sorghastrum nutans)• Eastern gamagrass (Tripsacum dactyloides) • Partridge pea (Chamaechrista fasciculata)

Fishing Point Maintenance

Annual mowing was conducted on the capped landfill to prevent woody species establishment form 2007 to 2010.

By 2009 sericea lespedeza (Lespedeza cuneata) was a major component of the grassland area.

Sericea Lespedeza Control – YR 1

In 2011 herbicide use and prescribed fire were introduced as maintenance tools for controlling lespedeza and woody species.

In August 2011, the lower portion (green) of Fishing Point was mowed. The upper portion was left unmowed.

In October 2011, the entire site was treated in with 2% triclopyr solution to control the lespedeza.

In March 2012, a controlled burn was conducted on the upper portion (red).

Prescribed Burn – YR 1

The burn was successful in:• Removing accumulated vegetative debris

Less effective in: • Removing lespedeza, • Japanese honeysuckle (Lonicera japonica), • Fescue (Schedonorus arundinaceus).

A patchwork mosaic of burned and unburned areas resulted.

Prescribed Burn Results - YR 1

By May 2012, two months after the prescribed burn, switchgrass was the dominant species.

Vegetation was sparse in a few areas. Some less desirable species (ragweed) and some lespedeza were also present.

Unburned Area Results – YR 1

On the unburned portion of Fishing Point, lespedeza was still the dominant species.

Non-native clover was also abundant. White clover (Trifolium repens) and field clover (Trifolium campestre) are seen here.

Burned / Unburned Area Comparison – YR 1

By July 2012, the burned portion had developed a dense cover of native grasses.

The unburned portion had developed a dense cover of sericea lespedeza.

Sericea Lespedeza Control – YR 2

Herbicide treatments of the entire area were again conducted in 2012.

Mowing was conducted on the upper portion (green).

In March 2013, the lower portion (red) of the site was burned.

Sericea Lespedeza Control – YR 2

In September 2012, the entire site was again treated with a 2% solution of triclopyr.

In March 2013, the lower portion of the site was burned.

Prescribed Burn Results - YR 2

By July 2013, dense NWS grasses were well established in both the burned and unburned areas.

Switchgrass was still the dominant species.

Only small patches of lespedeza occurred, which were treated with triclopyr in July 2013.

Continued Maintenance at Fishing Point

The two portions of Fishing Pont will be burned on a three-year cycle. Herbicide use is expected to be minimal in future years.