Lepidium latifolium
A.K.A.
•Dittander
•Dittany
•Broad-leaf Pepperweed
•Peppergrass
•Pepperwort
•Perennial Peppercress
•Perennial Pepperweed
•Tall Pepperweed
•Tall Whitetop
•Whitetop
•Ect., ect., ect.
Characteristics:
 Perennial herb
 Brassicaceae (Mustard
Family)
 Related to broccoli,
beets, cabbage, canola,
and other crops
 Erect, up to 6 feet tall
 Roots up to 10 feet long!
 Distinguish rosettes from
natives with long
stemmed leaves (natives
are sessile)
Native Range (uncommon)
North American Distribution (very common)
Where is it?
Native to SE Europe
& SW Asia, uncommon
Arrived with beet
seed from Europe
before 1840
17 million acres in
West
20,000 acres of the
Truckee river
Primarily a riparian
species
But, is now found in
drier rangelands
Is it adapting more?
Why are they doing so well?
Characteristics
A. Extremely long straight
taproots
B. Can tolerate saturated soil
for long periods
C. Sprouts from root
fragments (like a potato)
D. Alters soil characteristics
E. Tastes really BAD
Competition
 Gets to the water table
faster than natives
 Survives flooding
 Survives trampling
 Sucks up Ca+ salts and
leaves it on top of soil
 Cattle and deer avoid it
How it is changing
our landscape.
•Displacing native
vegetation
•Bad forage
•Take up a lot of
water
•Increasing
stream incision
•Creates light
impermeable
layer of duff
How does it fit our 10 hypothesis?
Competition
hypothesis:
• Definitely!
• Takes over riparian
areas
• Shades out
neighbors
• Reaches water table
better
Escape from enemy
constraints:
• Maybe…
• Biocontrols are
under study
• Not sure if bugs are
limiting
• Don’t care
How does it fit our 10 hypothesis?
Variable Resource Availability:
Disturbance and Land use:
• Ruderal species
• Grows tall fast
• High density +
long root = lowers
water table below
what natives are
used to
• Riparian areas
frequently
flood
• And frequently
damaged by
livestock
Approved Herbicides
(you’re going to need a LOT)
Telar®
(chlorsulfuron)
Noncrop
Industrial
Selective herbicide
(will not harm most
grasses), do not apply
near water.
Excellent control for 12 years
Habitat® (imazapyr)
Riparian
Wetland
Nonselective
herbicide, do not
apply near water
Stalker® (imazapyr)
Wildlands
Excellent control for 12 years. Treated areas
typically remain void
of any vegetation for
1-2 years after
treatment.
Roundup® and others
(glyphosate)
Wildlands
Nonselective
herbicide. Rodeo® for
areas near/in aquatic
sites.
Effective unless
infestation is dense. If
dense, mow area and
apply to resprouting
plants.
Rodeo®, Aquamaster® Aquatic
and others
(glyphosate)
Weedar 64®
(2,4-D)
Wildlands
Aquatic
Selective herbicide
Somewhat effective
(will not harm grasses) unless infestation is
dense. If dense, mow
area and apply to
resprouting plants
Methods of Control
and other Theories
Submerging for a very
long time (2years?)
Mow and spray with
white leaf rust (fungus)
Mite from Turkey
Leaf hopper from Elko
Stem boring maggots
Goats !!
Can be trained to selectively eat
perennial Pepperweed
Sources Cited:
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http://plants.usda.gov/java/profile?symbol=LELA2
http://www.unce.unr.edu/programs/sites/tallwhitetop/
http://www.fs.fed.us/database/feis/plants/forb/leplat/habitat.jpg
http://www.nps.gov/plants/alien/fact/lela1.htm
http://www.invasivespecies.net/database/species/ecology.asp?si=996&fr=1&sts=&lang=EN
http://www.weedid.wisc.edu/idpics/sized_650/lepidium_latifolium4_650.jpg
http://flora.nhm-wien.ac.at/Seiten-Arten/Lepidium-latifolium.htm
• Brain Rector, Elizabeth Leger, and of
course….Robert Nowak & Erin Georgen