PERENNIAL PEPPERGRASS 
A Noxious Weed in Colorado 
By A. K. Peitersen and R. T. Burdick 
I. Introduction — Recently the perennial peppergrass has become 
of such frequent occurrence in Colorado that unless prompt action 
be taken for its control it is almost certain to spread itself over 
most of the cultivated areas of the state. During the past season this 
station has received numerous urgent appeals for some definite 
advice concerning methods for controlling this pest. These appeals 
have come from widely different sections within the state. It Avas 
therefore thought that a preliminary report on this noxious Aveed 
might be timely in acquainting the farmers of the state Avith the 
characters of this introduced plant and in this way its introduction 
into uninfested areas might be preA^ented. Preventing its introduc- 
tion into new fields is far easier than prescribing methods for its 
eradication Avhen once established. 
II. Name and Description — The perennial peppergrass is bo- 
tanically known as Lepidium draba L. but in common Avith other 
plants which are of economical importance or which have attracted 
the attention of the passer-by it is recognized by a number of com- 
mon names such as : Perennial Peppergrass, Hoary Cress, Turkestan 
Mustard, White Weed, and a number of other local names Avhich 
are generally descriptive of the plant. In the San Luis Valley it is 
commonly referred to as the Perennial Peppergrass, while in the 
Grand Valley it is more frequently called White Weed. The former 
name, however, is used most generally throughout the United States. 
This plant is ah erect perennial, ten to tAventy inches high, hav- 
ing a much-branched inflorescence, spreading profusely by under- 
ground root stocks. Its leaves are oblong or lanceolate, obtuse and 
slightly toothed, 11/2 to 3 inches long, whitish-pubescent, the upper 
sessile and clasping the stems, the lower long and petioled. Inflores- 
cence consisting of white, showy flowers ; pedicels long ; the 2 - 
carpellate pistil ripening into a flattened fruit having a slender 
style about Vg inch long; pods somewhat heart-shaped and wing- 
less, usually containing one mature seed; seeds dark brown, some- 
what tapering at one end and about the size of alfalfa seed. (See 
Plate I.) 
