Leafy spurge [Euphorbia
esula L.][EPHES][CDFA list: A][CalEPPC list: A2] Photographs
Map of Distribution
Oblong spurge [Euphorbia
oblongata Griseb.][Bayer code: none] [CDFA list: B] Photographs
Map of Distribution
Toothed spurge or Serrate
spurge [Euphorbia serrata L.][EPHSR][CDFA list: A] Photographs
Map of Distribution
DESCRIPTION:Noxious perennials with
milky white latex to 0.8 m tall. Introduced from southwestern Europe.
SEEDLINGS:leafy spurge: Hypocotyl dull reddish-brown at the soil
line, pale green above. Outer root tissues becoming brown and corky at an
early stage. Cotyledons linear to elliptic, 2-4 mm wide, 4-19 mm long, becoming
leaf-like with age. Upper surface covered with white powdery granules. Lower
surface pale and conspicuously veined. Seedling leaves similar in shape to
mature leaves except smaller. First leaves opposite. Subsequent leaves alternate
but close together so as to appear sub-opposite. Leaf pairs folded or rolled
longitudinally in bud, with one leaf enclosing the other. Seedlings develop
adventitious buds near the soil line at an early stage. Seedling descriptions
for oblong and toothed spurges are unavailable.
to top of page
PLANT:Stems +/- woody at the base. Leaves
sessile, glabrous, mostly alternate (some may be opposite or whorled
just below the inflorescence branches). Inflorescence bracts opposite, cordate
to kidney-shaped, sessile, glabrous, shorter and broader than leaves. Stipules
and UNDERGROUND STRUCTURES:
FLOWERS:Monoecious (male and female flowers separate on same plant).
Infloresences umbel-like at the stem tips, with the central inflorescences
maturing first (cyme-like). Each infloresence appears to consist of one flower,
but is actually a cluster of reduced unisexual flowers (cyathium). A cyathium
consists of several staminate (male) flowers, each reduced to 1 stamen, inserted
on a glabrous bell-shaped hypanthium (receptacle extension) and one pistillate
(female) flower situated above the staminate flowers on a stalk from the center
of the hypanthium. Each pistillate flower has 3 styles fused together at the
bases and branched at the tips and a 3-chambered ovary. The rim of the hypanthium
has 4 flattened glands that lack petal-like appendages.
and SEEDS:Capsules round, 3-chambered, with
1 seed per chamber. Seeds ovoid to oblong, round in cross-section, 2-3 mm
long, and with a yellowish caruncle (small elaisome) near the end of attachment.
CHARACTERISTICS:Leafy spurge shoots
die back with the onset of the cold season. Leaves often turn reddish just
before dropping. About 42 days of chilling are required to release plants
from postsenescent dormancy.
HABITAT: Waste areas, disturbed sites,roadsides, fields, pastures.
leafy spurge: Also, rangeland,
alfalfa fields, riparian areas. Plants tolerate sub-tropic to sub-arctic climates,
xeric to mesic conditions and flooding for at least 4-5 months if shoots can
grow above the water surface. Grows best on coarse-textured soils, although
most soil types are tolerated.
PROPAGATION/PHENOLOGY:Mature capsules of many spurges rupture and forcefully eject
seeds some distance from the parent plant.
FAVORING/DISCOURAGING SURVIVAL:Wearing gloves
while handling plants can prevent skin irritation from the sap.
leafy spurge: Mowing, burning,
and grazing do not significantly affect roots and typically stimulate the
production of new shoots from root buds. Continuous grazing by sheep or goats
can reduce the soil seed bank by preventing flower production, but roots can
continue to produce shoots for many years (>8 years). Livestock, especially
sheep and goats, foraging on plants in fruit should be quarantined for 5-6
days before transporting to uninfested areas to prevent the introduction of
seed. Cultivation or discing can spread infestations by transporting root
fragments and seeds.
SPECIES:There are many weedy spurge species,
several of which appear similar. Refer to the tables Spurge: vegetative
characteristics and Spurge: reproductive characteristics for comparison.
The following species are most likely to be confused with leafy, oblong,
and toothed spurges.
sun spurge, wartweed
[Euphorbia helioscopia L.][EPHHE]: Annual to 0.5 m tall.
Flowers March-August. Disturbed sites, waste areas. Northern and central North
Coast, northwestern and central-western North Coast Ranges, San Francisco
Bay region, South Coast. To 200 m (650 ft). Introduced from Europe.
caper spurge, gopher plant
[Euphorbia lathyris L.][Cal EPPC list: need more information]:
Potentially noxious annual or biennial with opposite leaves,
to 1 m tall. Flowers most of year. Disturbed sites, waste areas, roadsides,
coastal scrub, marshes, dunes. North, Central, and South Coasts, Central Valley.
To 200 m (650 ft). Introduced from Europe.
[Euphorbia terracina L.]: Potentially noxious perennial or biennial,
to 0.5 m tall. Often forms dense patches. Flowers March-(August). Disturbed
areas, including disturbed grasslands, coastal bluffs, dunes, salt marsh,
riparian areas, oak woodlands. Uncommon. South Coast (Los Angeles Co.). Recently
introduced from southern Europe and the Mediterranean.
to top of page
Prevention: Leafy spurge
is an extremely noxious weed found throughout the Western United States. It
is toxic when eaten by cattle and horses and may irritate the skin and eyes
of humans who come in contact with its milky latex. It reduces forage quality
and subsequent livestock carrying capacity. Leafy spurge is a very aggressive,
deeply rooted perennial that effectively competes with native plants. Established
stands are very difficult to control. It is classified as a CDFA class "A"
noxious weed and should be aggressively managed to prevent its spread. There
is considerable information regarding the control of leafy spurge, but little
is known about oblong or serrate spurge. Serrate spurge is also a class A
species and oblong spurge is a class B species. Regardless, they should also
be managed to prevent spread from known infestations.
Leafy spurge may be spread by humans, animals, equipment, and through contaminated
hay. It rapidly colonizes disturbed areas in pastures, rangelends, and roadsides.
It may also persist along waterways and riparian areas, and is often transported
by moving water. Cattle will generally avoid leafy spurge and subsequently
overgraze more desirable neighboring plants. This type of selection allows
leafy spurge to rapidly establish large dense stands. Therefore, avoid overgrazing
and excessive disturbance in pastures and rangelands, and reduce cattle stocking
rates in areas of known infestations.
Mechanical: Leafy spurge
will not usually persist in agricultural fields that use conventional tillage
practices. However, it can be a problem in fields where reduced or no-tillage
systems are used. Herbicide rates required for leafy spurge control will almost
always exceed rates allowed in cropping systems. Therefore, it may be necessary
to implement a cultivation program to reduce infestations. Two post-harvest
cultivations in the fall to a depth of at least four inches will help reduce
infestations. This should be conducted for two to three years. It is very
important to clean tillage equipment after cultivating fields infested with
leafy spurge, as plant regeneration can occur from very small root segments.
Hoeing, grubbing, or hand pulling leafy spurge is a very difficult task, but
may be used for small patches. These control methods will need to be repeated
several times over the growing season, due to regeneration of new shoots from
root buds. Long term control may require several years of diligence when using
these methods. Gloves are recommended when handling leafy spurge due to the
irritating effects of the latex. Avoid rubbing your eyes or face after handling
leafy spurge, and always wash with a detergent and warm water.
Mowing is generally not effective for reducing leafy spurge infestations.
However, mowing every 2-4 weeks can reduce seed production. Mowing may result
in more uniform spurge regrowth, which is more conducive to uniform herbicide
applications. However, this does not guarantee improved control.
Fire: Fire has not generally
been successful for controlling leafy spurge, due to rapid regeneration. Fire
may be beneficial in other ways, by removing litter and dead stems. Fire may
also stimulate bunchgrass growth, which may improve its competitive ability
with leafy spurge.
Biological: There are no
current biocontrol programs for oblong spurge or serrate spurge. However,
there are several insects approved for use as leafy spurge biocontrol agents
in the United States. To date, none are known to have established in California.
Five flea beatles (Aphthona spp.) have been established in many areas across
the Great Plains and Pacific Northwest. They are destructive in a two-fold
manner. The larvae feed on the root hairs and roots, and the adults feed on
the stems, leaves, and flowers. Flea beetle establishment may take three to
five years, and success varies with differing environmental conditions. Once
established, flea beetles may significantly reduce spurge populations. However,
new shoots will emerge from dormant root buds on undamaged roots.
Three moths (Chamaesphecia spp.) are being tested but are not currently available
for distribution. They are destructive in the larval stage by feeding in the
roots. Another moth (Hyles euphorbiae) has been established in certain areas,
but is not effective when used alone. These and other insects may eventually
provide long term leafy spurge management, but should not be used alone where
eradication is the objective.
Table 1. Insect species introduced
into the United States for the control of leafy spurge
Grazing: Although leafy
spurge is toxic to cattle and horses, goats and sheep are tolerant and have
been successfully used in control programs. A grazing program should be implemented
in the spring when leafy spurge emerges. Researchers at North Dakota State
University recommend sheep stocking rates of 3-6 head per acre of leafy spurge
infested land per month, or 12-16 Angora goats per acre of leafy spurge per
month. These animals will not eradicate leafy spurge, but will allow grasses
to more effectively compete and become established. It is extremely important
to place animals in a holding pen for 3-5 days before moving to a new area.
This will prevent viable seed from being dispersed to new areas through the
A dual grazing-herbicide strategy that allows for leafy spurge regrowth in
the fall followed by a herbicide application has been proven more effective
than either strategy alone. Interactions between biocontrol insects, herbicides
and grazing are not fully understood. However, where flea beetles are established,
herbicide applications can affect flea beetle populations by removing their
food source. The gall midge (Spurgia esulae) has been shown to be compatible
with herbicide applications, as long as a few patches are left untreated to
sustain the gall midge population.
Competitive species: There
is little information regarding establishment of competitive native species
on leafy spurge infested land in California. Research from North Dakota State
University indicated that Russian wildrye, pubescent wheatgrass, smooth brome,
western wheatgrass, and Dahurian wildrye, were competitive with leafy spurge.
These may or may not be desirable replacements, according to the goals and
objectives of the land manager.
Chemical: Leafy spurge is
very resilient to most herbicides due to regeneration from dormant root buds.
Its extensive root system maintains a large pool of carbohydrates that allow
for rapid shoot regeneration. One herbicide application will not provide long
term control, and retreatment will be necessary for several years. Application
timing is critical for herbicide effectiveness. Dicamba (4-8 lb ae/A) and
2,4-D (1-6 lb ae/A) are most effective when leafy spurge plants are flowering
in early summer, or during he fall when regrowth has occurred. The lower rates
will prevent seed production but will not provide long term control. Glyphosate
(0.38-0.75 lb ae/A) is more effective after plants have begun filling seed.
However, this will allow for some seed production and may not be the best
strategy for an eradication program. Another strategy is to apply glyphosate
in split applications over the summer in June, July, and August. This will
control emerged plants and prevent seed production. The most effective herbicide
for leafy spurge control is picloram at 0.5-2 lb ae/A. However, picloram is
not labeled for use in California.
These rates of dicamba and 2,4-D will initially have a severe impact on desirable
forbs and legumes, and yearly repeat herbicide applications may substantially
reduce their recovery. Glyphosate is nonselective and will injure or kill
other vegetation it contacts. Where infestations occur along water, an aquatic
formulation of glyphosate (Rodeo) or 2,4-D can be used to prevent seed production.
In wooded areas, dicamba may not be used and either glyphosate or 2,4-D amine
formulation can be applied. It is very important to minimize drift in these
areas, as significant injury to trees and shrubs may occur. It is also recommended
that herbicide applications extend 3-5 m beyond patch edges due to the creeping
nature of the roots. Herbicide use for managing leafy spurge is very costly
and must be integrated with other strategies for long term success. Any control
efforts not maintained on a yearly basis will result in complete and rapid
Integrated management: The
best defense against leafy spurge is preventing infestation. Rapid identification
and response may prevent leafy spurge from becoming a problem. Small patches
should be aggressively controlled and monitored often for regrowth. Once infestations
become larger, control is very difficult and costly. No single control measure
will eliminate leafy spurge. However, integrative methods that utilize a number
of techniques have been shown to successfully control infestations. There
is also an interactive compact disc entitled "Purge Spurge: Leafy Spurge
Database" which was developed by the United States Department of Agriculture/Agricultural
Research Service, in conjunction with Montana State University. This is a
comprehensive source of information on the biology and control of leafy spurge
and is very easy to use. More information is available at the web site: http://www.sidney.ars.usda.gov