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Weed Identification and Control Sheet:
Leafy Spurge (Euphorbia esula)
www.goodoak.com/weeds
DESCRIPTION:
Leafy spurge is legally classified as a noxious weed in nineteen states including Wisconsin.
Grazing land productivity can drop 50 to 75% because leafy spurge is poisonous to most livestock. In natural areas leafy spurge displaces native grasses and forbs by beginning growth early in the spring. This
head start allows it to shade out competitors, potentially reaching a density of 1,800 stems per square
yard. Leafy spurge also produces chemicals that interfere with the growth of
other plant species. This plant spreads vegetatively and by seed. The primary
method of expansion into natural areas are by laterally moving underground
roots (rhizomes). The extensive rhizomes can spread 35 ft. laterally, which
allows for regeneration after vegetation damage. Leafy spurge can produce
200 seeds per plant, which can be expelled up to 15 ft. when ripe, usually in
July. The seeds of leafy spurge have a high germination rate and remain viable
in the soil for up to 8 years. Leafy spurge prefers open sun, but can tolerate
partial shade and is most aggressive on drier sites.
IDENTIFICATION:
Leafy spurge most commonly grows to a height of 12-30”. The leaves
have a bluish green color that are long, narrow, pointed, and drooping with
smooth margins. The flower is green and very small with petals that are fused
together and blooming from mid-June to August, with some blooming into fall.
The yellow-green and heart shaped bracts are the most colorful part of this
plant, and are found just below the small green flower. These bracts open
late May to early June. When damaged, leafy spurge, like all members of the
spurge family, releases a milk-like, sticky white sap.
CONTROL METHODS:
Organic: No organic method have been proven successful in controlling
leafy spurge. Digging may be attempted for small infestations, but the entire root
system needs to be removed for the best results. If root fragments are left in the
soil, the number of plants may actually increase. Studies have shown that spring burning may
decrease seed germination, but it also stimulates leaf production. Mowing decreases seed production, but does nothing to the spreading root structure. Early detection is imperative.
Chemical: This species is resistant to many types of herbicide. 2-3 treatments through a
single growing season will be needed for control: first when it sprouts and reaches ~6” in height
in mid-spring, second when it begins to flower in early-summer and finally with any new sprouts
that emerge in early-to-mid fall. This will likely need to be repeated for several years before the
population can be eliminated.
One chemical that has a proven effective track record is Perspective®. This chemical has a
high potential for damage to neighboring broadleaf plants through root uptake, use with caution.
We recommend using the “glove-of-death” application technique when it is mixed in with desirable
plants. See label for application rate recommendations. For
best performance, add an adjuvant such as 2.0 oz of MSO to
the spray solution.
Aminopyralid (Milestone®) & clopyralid (Transline®)
are moderately effective against this species. Other chemicals that have had a variety of success are imazapic (Plateau®,
etc.) and fosamine (Krenite®, etc.). Imazapic is a selective
herbicide that may harm cool season grasses, but not warm
season grasses. Imazapic should be applied in the fall before
frost. When using imazapic be wary of the water table because it may leach into the groundwater on sandy soils. Using
fosamine after a spring burn on resprouts that began blooming
in June/July has shown success.
Always read herbicide labels carefully before use and
always apply according to the instruction on the product
label.
All content © Frank Hassler, 2015, unless otherwise noted.
Updated:
4/23/15