Green kyllinga, Kyllinga brevifolia , is
a weedy sedge that is becoming a
major problem in turf and ornamental
plantings in California. The genus
Kyllinga consists of about 40 species
that are distributed worldwide in
subtropical and warm temperate
regions. Green kyllinga has been
reported as a weed problem from
Florida across the Southeastern United
States into Arizona, California, and
Hawaii. In California it occurs from San
Diego to the Sacramento Valley. Green
kyllinga is believed to have originated
in Asia and was reported as a weed
in California more than 50 years ago.
However, it has developed into a major
problem for turfgrass and landscape
managers during the last 10 to 15 years.
Green kyllinga is sometimes confused
with purple or yellow nutsedge, but
its growth habits, reproduction, and
morphology are different.
IDENTIFICATION AND
LIFE CYCLE
Green kyllinga (Figure 1) is a perennial
plant that grows best in moist or wet
areas that receive full sun, but it can
survive some shade and drying once
established. Green kyllinga grows well
in warm weather from April through
October. It is dormant in winter but
remains green in warm climates where
freezing doesn’t occur. It can yellow
in the winter but doesn’t turn brown
when it goes dormant. When left
unmowed, green kyllinga can reach a
height of about 15 inches but will adapt
and grow in a prostrate manner if
mowed. The plant produces a network
of numerous underground stems
(rhizomes) and can root and send out
new leaves at each stem node. If green
kyllinga rhizomes are removed and
chopped into pieces, new plants can
be produced from each node or stem
section. Rhizomes in soil will begin
to produce long, narrow leaves that
are 1 to more than 5 inches long as
temperatures rise in the spring.
Green kyllinga stands out in turf due
to its different texture and growth rate
and is easily identified by its flower
stalk. Flowering usually occurs from
May to October, but it can occur earlier
in warm locations. Flower stalks are
triangular in cross section and 2 to 8
inches long. The stalks terminate in a
globular inflorescence (flower head)
that is green and about 3/8 inch in
diameter. Directly below the flower is
a group of three leaves that radiates
out from the stalk. There are 30 to 75
spikelets within each flower, and each
of these is capable of producing one
seed. A mature plant can produce more
than 100 flowers within a growing
season and up to 5,000 seeds.
The seed of the green kyllinga plant
is highly viable and contributes
significantly to the spread of this
plant. It has an oval shape, is flat in
cross section, and is about 1/8 inch long
and 1/16 inch wide. Seed germination
occurs at or very near the soil surface.
Burying seed as little as 1/3 inch below
the soil surface reduced germination
twelvefold in one Arizona study.
The tan-colored seeds germinate
when soil moisture is adequate and
soil temperatures reach about 65°F.
Germination continues throughout
the summer. Seedling growth is slow
initially, and plants might require
several weeks to become established.
Once established, green kyllinga forms
a vigorous system of rhizomes that
allows lateral spread and production
of new plants. It can survive and even
flower and produce seed at mowing
heights of 3/4 inch.
Green kyllinga can be confused with
yellow or purple nutsedge because
they grow in similar locations. Often
green kyllinga can be recognized by
its habit of growing in continuously
enlarging patches similar to rhizomous
turfgrasses. Yellow and purple
nutsedge appear more commonly
as individual plants and have much
wider leaves than the finer-bladed
green kyllinga. Also, green kyllinga
has a small, round seed head whereas
nutsedges have an open spikelet. The
flower and rhizomes of the green
kyllinga plant and the absence of
under
ground tubers make it easy to
distinguish from nutsedges (Table 1).
IMPACT
Green kyllinga can be a major weed
problem for turfgrass and landscape
managers. In turf it forms a weak sod
that gives poor footing for athletic
fields and golf courses. Although green
kyllinga is most often a problem in
bermudagrass, it has been found in
cool-season turf species as well. Green
kyllinga has a texture and color that
varies from normal turfgrass species
and reduces the aesthetic quality of the
turf. Also, green kyllinga grows faster
than most turfgrass species, which
gives infested turfgrass an undulating
or irregular surface in as little as two
days after mowing.
Integrated Pest Management for Home Gardeners and Landscape Professionals
G reen K yllinGa
Figure 1. Mature green kyllinga plant.
Statewide Integrated Pest Management Program December 2011
P EST N OTES Publication 7459
December 2011 Green Kyllinga
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Once a few plants become established
in turfgrass or ornamental areas,
spread can be rapid. In warm weather,
rhizomes can grow by more than 1
inch per day, forming thick mats in
just a few weeks. Mowing, foot traffic,
and cultivation spread both seed and
rhizomes. This allows the production
of new plants and hastens spread.
MANAGEMENT
The best management approach
is to prevent new infestations by
excluding and monitoring for the
weed. Thoroughly clean mowers and
cultivation equipment before moving
from infested to weed-free areas. If
solitary plants of green kyllinga are
found, they should be grubbed out
(i.e., remove the entire plant, roots
and all) and the area monitored for
several months to ensure removal was
complete.
When green kyllinga infests
ornamental plantings, it forms a dense
mat that crowds out desirable species
and reduces the vigor of those plants
that survive. Because of the extensive
rhizome system in established stands,
hand pulling or hoeing to remove
green kyllinga usually is futile unless
done repeatedly over a long period
of time. Digging out plants and
surrounding soil with a shovel is
likely the best approach for removing
rhizomes, although plant removal
can be very expensive and not always
successful. Once established green
kyllinga will continue to spread unless
control measures are taken.
Turfgrass and ornamental areas
should be well maintained to promote
maximum vigor and make these
plantings as competitive as possible to
hinder invasion by the weed. Dense
turfgrass and ornamentals will shade
the soil surface, making establishment
of green kyllinga seedlings difficult.
Irrigation systems should be adjusted
and managed to eliminate wet
conditions that favor green kyllinga.
Turfgrass
Controlling green kyllinga in turfgrass
requires a combination of control
procedures. Wet or overwatered areas
in turfgrass provide ideal habitat
for a green kyllinga invasion. To
reduce the chance of invasion or slow
the invasion into turfgrass, don’t
overwater the turf. If low areas stay
wet, improve drainage or reduce water
applications in that area.
Early grubbing of solitary infestations
has been successful when practiced
diligently. Spot spraying isolated
plants with glyphosate can be helpful,
but the turfgrass also is killed, leaving
open areas that allow reestablishment
of kyllinga or invasion of other weed
species. The open spots should be
overseeded or patched with sod to
establish a vigorous turf.
Mowing and nitrogen fertilization also
affect the growth of green kyllinga. In
one study on hybrid bermudagrass,
low mowing (i.e., 1 inch compared
to 2 inches) resulted in increased
green kyllinga seed germination and
growth in established turf provided
with adequate nitrogen. However, in
newly established turf where there
was significantly more green kyllinga
Table 1. Distinguishing Characteristics of Green Kyllinga and Yellow Nutsedge.
Green kyllinga Yellow nutsedge
Growth habit
continuously enlarging patches, almost as a tur f usually individual plants or, when young, connected widely by rhizomes
Seed head/flower
small, round open spikelet
Below- ground propagation method
rhizomes; no tubers tubers
J. K. Clark J. K. Clark
J. M. DiTomaso J. K. Clark
J. K. Clark J. K. Clark
December 2011 Green Kyllinga
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present, the mowing height didn’t
have as great an effect, and additions
of nitrogen resulted in increased turf
cover and less spread of green kyllinga.
Unfortunately, eradication wasn’t
possible with any mowing height or
nitrogen rate.
Chemical control of green kyllinga
may be achieved with preemergent
herbicides applied before the seeds
germinate, with selective postemergent
herbicides for established plants or
with a combination of preemergent and
postemergent herbicide treatments. The
use of herbicides can be very effective if
combined with cultural methods such
as water management and exclusion of
green kyllinga from turf and landscape
areas.
Preemergent herbicides have been
successful in limiting germination of
green kyllinga seeds. These herbicides
should be applied in spring before
soil temperatures reach 60°F to limit
germination in late spring and early
summer. Preemergent materials that
are effective include benefin, bensulide,
dithiopyr, pendimethalin, and
prodiamine.
Postemergent herbicides can limit
growth of green kyllinga. Herbicide
products available for green kyllinga
and plants in the sedge family contain
halosulfuron, imazosulfuron, MSMA,
or trifloxysulfuron. Be sure to select a
product that is safe for your existing
turfgrass species. The best control has
been obtained when halosulfuron is
applied in two sequential applications.
Make the second halosulfuron
application when kyllinga plants show
signs of recovering.
Even when herbicides are used for
control, be sure the turfgrass has
adequate drainage to reduce the
potential for proliferation by this weed.
If turfgrass areas are to be completely
renovated with new turf from seed, sod,
or stolons, the existing plant material—
including green kyllinga—can be
treated with a nonselective herbicide
such as glyphosate prior to planting.
Ornamental Landscapes
There are few options for the control
of green kyllinga in ornamental
landscape plantings. Prevention is
very important. Hand removal or spot
spraying of solitary plants as soon
as they are found will save time and
money in the long run. Cultivation or
hand hoeing must be done carefully,
because hoeing can break rhizomes
into smaller pieces and “transplant”
them to new areas. This is particularly
true if irrigation follows hoeing.
Mulching with landscape fabrics (e.g.,
geotextile mulches) can be effective
if fabrics are overlapped and no light
is allowed to penetrate to the soil.
Geotextile mulches combined with
hand removal should provide adequate
control of green kyllinga in perennial
planting beds. Use a polypropylene or
polyester fabric or black polyethylene
(plastic tarp) to block all plant growth.
Wood chips or bark should be placed
on top to inhibit breakdown by UV
light. Plant-derived mulches (i.e.,
organic mulches) alone might not
effectively control kyllinga, because it
will probably grow through the mulch.
Preemergent herbicides such as
oryzalin and pendimethalin can be
used to limit seedling germination
in sites where their use is permitted.
Make applications in April before soil
temperatures reach 60°F. Preemergent
herbicides will be of little benefit if
estab
lished kyllinga plants are present.
Postemergent herbicides containing
halosulfuron are registered for use
in established ornamental plantings.
Spot treatment with glyphosate can
reduce green kyllinga’s growth, but
don’t let the spray come in contact with
desirable plants or injury will result.
REFERENCES
Bryson, C. T., et al. 1997. Kyllinga, A
genus of neglected weeds in the
continental United States. Weed Tech.
11(8):838–842.
Kawabata, O., R. K. Nishimoto, and C.
Tang. 1994. Interference of two kyllinga
species ( Kyllinga nemoralis and Kyllinga
brevifolia ) on bermudagrass ( Cynodon
dactylon ) growth. Weed Tech. 8(1):3–86.
Lowe, D. B., T. Whitwell, L. B. McCarty,
and W. C. Bridges. 2000. Mowing and
nitrogen influence green kyllinga
(Kyllinga brevifolia ) infestation in Tifway
bermudagrass ( Cynodon dactylon X C.
transvaalensis ) turf. Weed Tech. 14(3):471–
475.
McElroy, J. S., F. H. Yelverton, and L. S.
Warren Jr. 2005. Control of green and
false-green kyllinga ( Kyllinga brevifolia
and Kyllinga gracillima ) in golf course
fairways and roughs. Weed Tech. 19(4):
824–829.
Molin, W. T., et al. 1997. Green kyllinga
(Kyllinga brevifolia ): germination and
herbicidal control. Weed Sci. 45(4):546–
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AUTHORS: D. A. Shaw , UC Cooperative Extension, San Diego Co.; C. A. Wilen , UC Statewide IPM Program, San Diego Co.; D. W. Cudney , Botany and Plant Sciences emeritus, UC Riverside; and C. L. Elmore , Plant Sciences emeritus, UC Davis.
TECHNICAL EDITOR: M. L. Flint
EDITOR: M. L. Fayard
ILLUSTRATION: Fig. 1 , D. W. Cudney.
This and other Pest Notes are available atwww.ipm.ucdavis.edu.
For more information, contact the University ofCalifornia Cooperative Extension office in your county. See your telephone directory for addresses and phone numbers, or visit http://ucanr.org/ce.cfm.
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Produced by UC Statewide Integrated Pest Management ProgramUniversity of California, Davis, CA 95616
Universit y of California scientists and other qualified professionals have anonymously peer reviewed this publication for technical accuracy. The ANR Associate Editor for Urban Pest Management managed this review process. To simplify information, trade names of products have been used. No endorsement of named products is intended, nor is criticism implied of similar products that are not mentioned. This material is partially based upon work supported by the Extension Service, U.S. Department of Agriculture, under special project Section 3(d), Integrated Pest Management.
