Coastal areas of northeastern Asia
Asiatic sand sedge is a perennial
adapted to coastal beaches and dunes and possibly the only Carex species found
in upper beach habitat along the U.S. Atlantic Coast. The mature sedge is a coarse
and stout member of the genus that forms extensive colonies through cord-like
rhizomes that extend many feet under the sand and produce new shoots. Flowering
and fruiting occurs April through June and individual plants have either male
or female flowers. As with many other members of the genus Carex, the flowers
are numerous, subtended by scales, and arranged in spikes at the end of a flowering
stalk that is triangular in cross section. A papery sac or perigynium encloses
the female flowers, each of which develops into a single-seeded fruit, called
Because flowering culms are evident for a relatively brief period during
the spring, and some colonies and new
infestations may spread extensively without flowering, it is useful to learn
to recognize the plant in its sterile form. Asiatic sand sedge may be confused
with at least two colonial, rhizomatous native grass species - American beach
grass (Ammophila breviligulata) and beach panic grass (Panicum amarum).
Leaves of Asiatic sand sedge are longer tapering than those of the above grasses,
have a yellow-green rather than bluish-green cast, and small teeth along the
margin that are easily felt or seen with the help of magnification. These differences
become more obvious when observed in the field. Several species of another
sedge genus, Cyperus, sometimes grow on dunes and on wash flats and strongly
resemble Carex when not in flower. However, these Cyperus species flower from
late summer to fall, have leaves without serrated margins and, unlike Asiatic
sand sedge, are weakly to non-rhizomatous.
Asiatic sand sedge
invades wash flat habitat occupied by the federally listed plant, seabeach
amaranth (Amaranthus pumilus), which is a poor competitor against
it. On established, vegetated sand dunes, Asiatic sand sedge can out-compete
native dune-binding grasses, like American beach grass and sea oats (Uniola
paniculata). Dunes dominated by Asiatic sand sedge are also more vulnerable
to wind blowouts and storm erosion. There is evidence to suggest that fewer
native plant species, and fewer individuals, occur on dunes dominated by
Asiatic sand sedge than on comparable dunes dominated by the native American
IN THE UNITED STATES
Asiatic sand sedge occurs in maritime areas from
Massachusetts to North Carolina.
HABITAT IN THE UNITED STATES
sand sedge grows on primary dunes and on upper parts of ocean beach wash
flats that have recently been disturbed by ocean storms. Like American beach
grass, it appears to create more habitat for itself by trapping wind-blown
sand to form dunes. Sand burial appears to stimulate the growth of rhizomes.
Asiatic sand sedge was first
observed in the United States, at Island Beach, New Jersey in 1929. Specimens
were collected on the Virginia part of the Delmarva (Delaware-Maryland-Virginia)
Peninsula as early as the 1940s. Although the circumstances of its introduction
are unclear, sand sedge was apparently introduced intentionally for use as
a sand binder in erosion-prone areas and may have spread accidentally as
a result of its use as a packing material in ship cargo.
BIOLOGY & SPREAD
Asiatic sand sedge spreads primarily by vegetative means, through production
of rhizomes. Sexual reproduction, which requires both male and female plants
to be present, is not necessary for a colony to expand locally. Expansion
of a colony was observed at Island Beach, New Jersey, despite the absence
of any seedlings. Long-distance dispersal of Asiatic sand sedge is uncertain
but it is likely that its seeds are tolerant of salt water immersion and
carried by ocean currents and storm surges. Plant fragments may be dispersed
by ocean currents, and may remain viable after extended salt-water immersion,
but this has not been confirmed. Some observation suggests that inundation
by storm surges can kill growing plants. In newly forming colonies, sexual
reproduction may be somewhat limited, since plants of the opposite sex may
not occur nearby. Pollen may be carried long distances by the wind. Much
research is needed to gain a better understanding of modes of dispersal and
establishment of Asiatic sand sedge.
Various mechanical and
chemical methods have been used successfully in managing Asiatic sand sedge.
Regardless of method, it is important to avoid breaking underground parts and
leaving them untreated and to conduct follow-up monitoring and treatment if needed.
Mapping infestations with a Global Positioning System (GPS) prior to treatment
is very helpful for relocating sites, especially in sandy natural areas like
beaches with few permanent landmarks. Cooperation and coordination among coastal
area land managers should lead to more effective control.
Because Asiatic sand sedge is capable of forming extensive colonies, early
detection and treatment of infestations is critical for effective management.
The potential for considerable long-distance dispersal of seeds necessitates
routine monitoring and possible follow up treatments, even after it is believed
to be eradicated. Because of the likelihood of leaving viable below-ground
parts after an excavation, it is important to revisit the site in subsequent
years to ensure that an infestation has been eradicated.
Excavation of individual plants by digging and hand-pulling
is feasible and has been successful when used to control small infestations
(e.g., fewer than 200 shoots). This method may not be economically or logistically
feasible on larger control projects. Excavation generally involves digging
with a shovel under and around each individual plant shoot to expose and loosen
the roots. Individual shoots are often connected to other shoots by cordlike
rhizomes that are about ¼ inch thick and often of considerable length. Once
shoot and roots are loose, all rhizomes need to be gently excavated by hand,
following them through the sand to minimize breaking. Rhizome parts left buried
are likely to grow into new plants. Because the tips of new tillers (shoots)
can be sharp enough to puncture skin, it is important to wear thick gloves
when handling below-ground parts. Plants should be removed from the beach and
disposed of in habitat unsuitable for the sedge (e.g., lawns), spread out to
dry, or composted in black plastic until dead.
Larger colonies of Asiatic sand sedge that have formed considerable
dunes are probably most effectively controlled using chemical herbicides. A
2% glyphosate (e.g. Roundup®, Rodeo®, etc.) and water solution applied to the
leaves during the growing season has provided effective control. One or two
treatments in the same season followed by spot treatments are usually needed.
Mid-summer (June through July in Maryland and New Jersey) treatments are just
as effective as fall (October in Maryland) applications and allow for same
season monitoring and re-treatment. Because rhizomes can be extensive, follow-up
monitoring and treatment are necessary for several seasons to ensure long-term
Good coverage of herbicide is needed but can be difficult because of the plant's
narrow leaves. To help track application and to minimize misapplication and
waste, a colorant can be added to the spray solution. Herbicide applications
should be made when the chance of rain is low for at least six hours after
application and when winds are minimal (e.g., 0-7 mph), to minimize drift of
herbicide to non-target areas. Herbicide users should read and follow all label
instructions and, when possible, mix chemicals where a spill containment and/or
clean-up facility is available instead of on site. Transport of herbicide is
likely to be more rapid through sand than in other soils, and microbial activity
that can break down herbicides is likely to be low in beach sand. When it is
necessary to mix herbicide on the beach or dunes, it is recommended to mix
over a waterproof basin set on top of a waterproof tarp.
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS.
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
For more information on
the management of Asiatic sand sedge, please contact:
- Chris Lea, Assateague Island National Seashore,
Berlin, MD; chris_lea at nps.gov
- Greg McLaughlin, New Jersey Division of
Parks and Forestry, Office of Natural Lands Management, Trenton, NJ; gmclaugh at dep.state.nj.us
- Virginia Natural Heritage Program/Virginia
Native Plant Society fact sheet http://www.dcr.state.va.us/dnh/fscako.pdf
SUGGESTED ALTERNATIVE PLANTS
sand sedge was originally introduced as a dune stabilizer, although it is
apparently less effective in this role than native species, such as American
beach grass (Ammophila breviligulata), which occurs throughout the
North American range of Asiatic sand sedge. In the southernmost part of this
range, sea oats (Uniola paniculata) is the dominant native dune binding
Dune Restoration and Planting
successful control of Asiatic sand sedge has been achieved, establishing
native vegetation is an integral part of dune restoration. Native species
such as American beachgrass (Ammophila breviligulata) and sea oats
(Uniola paniculata) should be planted to protect vulnerable dunes
from storm damage and blowouts and to prevent re-colonization by Asiatic
sand sedge. American beachgrass establishes itself well on primary foredunes
were shifting sands are common and should be planted during late winter to
early spring. In primary backdune areas and places where sands are usually
more stable, consideration should be given to planting species such as seaside
goldenrod (Solidago sempervirens), beach panic grass (Panicum amarum),
dune panic grass (Panicum amarulum), and sea-rocket (Cakile edentula),
in combination with American beachgrass and sea oats.
Chris Lea, National Park Service,
Assateague Island National Seashore, Berlin, MD
Greg McLaughlin, New Jersey Division of Parks and Forestry, Office of Natural
Lands Management, Trenton, NJ
Jil M. Swearingen, National Park Service,
National Capital Region, Washington, DC
Helen Hamilton, National Park Service, Assateague
Island National Seashore, Berlin, MD
Fernald, M.L. 1950. Gray's manual
of botany, 8th ed. 1987 reprint. Dioscorides Press, Portland, OR.
Small, J.A. 1954. Carex kobomugi at
Island Beach, New Jersey. Ecology 35: 289-291.
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Asiatic Sand Sedge (Carex kobomugi). http://www.invasive.org/weedus/subject.html?sub=10110.
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Virginia Department of Conservation
and Recreation and Virginia Native Plant Society. Date unknown. (Fact Sheet)
Invasive alien plants of Virginia: Asiatic Sand Sedge (Carex kobomugi)
Plant Conservation Alliance, Alien Plant Working Group.