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, uncommonArrived with beet seed from Europe before 184017 million acres in West20,000 acres of the Truckee riverPrimarily a riparian speciesBut, is now found in drier rangelandsIs it adapting more?

Why are they doing so well?

CharacteristicsA. Extremely long straight

taprootsB. Can tolerate saturated soil

for long periodsC. 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:

• Ruderal species• Grows tall fast• High density +

long root = lowers water table below what natives are used to

Disturbance and Land use:

• Riparian areas frequently flood• And frequently

damaged by livestock

Approved Herbicides (you’re going to need a LOT)

Telar®(chlorsulfuron)

NoncropIndustrial

Selective herbicide (will not harm most grasses), do not apply near water.

Excellent control for 1-2 years

Habitat® (imazapyr)

Stalker® (imazapyr)

RiparianWetland

Wildlands

Nonselective herbicide, do not apply near water

Excellent control for 1-2 years. Treated areas typically remain void of any vegetation for 1-2 years after treatment.

Roundup® and others (glyphosate)

Rodeo®, Aquamaster® and others (glyphosate)

Wildlands

Aquatic

Nonselective herbicide. Rodeo® for areas near/in aquatic sites.

Effective unless infestation is dense. If dense, mow area and apply to resprouting plants.

Weedar 64®(2,4-D)

WildlandsAquatic

Selective herbicide (will not harm grasses)

Somewhat effective unless infestation is dense. If dense, mow area and apply to resprouting plants

Methods of Control and other TheoriesSubmerging 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:

• 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