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Hoary Cress (whitetop,
pepperwort)
Brassicaceae (=Cruciferae), the mustard family
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Background
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 Hoary cress (also known as whitetop) was introduced to the
U.S. from Europe in the late 19th century. It was first noted around
seaports on the east and west coasts, indicating seed may have been in the
soil that was used as ballast for sailing ships. Hoary cress spreads both by
seed and creeping roots, living in a wide variety of environmental
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Description
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Hoary cress is a perennial that grows up to 3 feet tall.
Leaves are grayish green, clasping, lightly
pubescent, up to 4 inches long,
and are shaped like arrowheads. Flowers are white with 4 petals, 1/4-inch
across, and bloom in April and May; these dense flower clusters give the
weed a flat-topped appearance early in the season, but this is lost as the
stem elongates. Two small, flat, reddish brown seeds are contained in each
of the heart-shaped seed pods.  |
Distribution
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 Hoary
cress is found throughout the U.S. except from southernmost California
across to the southernmost Mississippi, and is extensive in Idaho.
CONTROL:
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Control
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Some herbicides are registered for and effective on hoary cress. There are
no biological control agents for this weed.
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© 1999 University of Idaho:
Text and photographs for these pages from Idaho's Noxious Weeds, by
Robert H. Callihan and Timothy W. Miller (revised by Don W. Morishita
and Larry W. Lass).
Please contact: Ag Publishing, University of Idaho, Moscow,
Idaho 83844-2240; 208 882-7982 visit the Resources for Idaho website at
http://info.ag.uidaho.edu, for more information about this or other
publications.
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