170 
THE NATIONAL NURSERYMAN 
OUR FIFTY WORST WEEDS 
Descriptive List Which Aids Farmers and Nurserymen to Apply 
Proper Methods—Three Kinds of Weeds Described. 
The table printed herewith gives an alphabetical list 
of the 50 worst weeds of the United States, with informa¬ 
tion which will enable readers to identify them. This table 
is arranged with the idea of aiding farmers in applying 
the methods of controlling weeds described fully in Far¬ 
mers’ Bulletin 660, “Weeds and How to Control Them.” 
The following sums up the principles of control of weeds, 
which the author of the bulletin believes costs the Amer¬ 
ican farmer several hundred million dollars every year. 
Far more important than to kill weeds is to avoid hav¬ 
ing weeds to kill. In other words, the farmer should aid 
to prevent rather than cure the evil. A farm can be made 
almost free of weeds by strictly observing the following 
principles; (1) Prevent weeds from going to seed on the 
farm; (2) prevent weed seeds being brought to the farm; 
and (3) in the case of perennial weeds, prevent them 
from making top growth and thus finally starve out the 
underground parts. 
Annual weeds live only one year, maturing their seeds 
and then dying. Biennial weeds live two years; during 
the first year they grow rather slowly, producing usually 
a taproot and a rosette of leaves close to the ground, but 
the second year they send up flower stems that produce 
seed and then die. As the annuals and biennials propa¬ 
gate themselves by seeds alone, it is necessary to observe 
only the first two of the principles stated above in their 
control. 
Perennial weeds, on the other hand, produce each year 
underground parts, which live over to the next year and 
produce top growth. These weeds propagate themselves 
by their underground parts as well as by their seeds, and, 
even if prevented from going to seed, keep on growing. In 
dealing with perennials, therefore, it is necessary to ob¬ 
serve all three of the principles. 
Descriptive list of the fifty worst weeds of the United States. 
[A-annual, B-biennial, P-perennial.] 
Common name, botan¬ 
ical name, and dura¬ 
tion of life. 
Color, size and arrange¬ 
ment of flowers. 
Sections where in¬ 
jurious. 
Method of seed distri¬ 
bution; vegetative 
propagation of the 
perennials. 
Place of growth and 
products injured. 
Bermuda grass, wire- 
Purple; 1-12 inch; 
Maryland to Missouri 
Seeds sparingly; root- 
Fields and lawns; hoed 
grass (Capri ola dac- 
tylon), P. 
spikes. 
and southward. 
stocks. 
crops. 
Bindweed, field bind- 
White or pink; 1 inch; 
Entire United States, 
Grain and flax seeds; 
Rich, moist soils; grain 
weed (Convolvulus ar- 
venMs), P. 
Bindweed, wild morn- 
solitary. 
especially California. 
creeping roots. 
and hoed crops. 
White or rose; 2 
Mississippi Valley re- 
Grain and flax seeds; 
Rich prairie and river 
ing glory (Convolvulus 
septum), P. 
inches; solitary. 
gion. 
rootstocks. 
bottoms; corn and 
small grain. 
Bitterweed, fennel, yel¬ 
low dog fennel (Hel¬ 
en ium tenuifolium) , A. 
Yellow; % inch; head. 
Virginia to Kansas and 
southward. 
Wind, hay, animals. 
Meadows and pastures; 
injures live stock and 
taints milk. 
Broom sedge (Andropo- 
Green; 14 inch; race- 
Massachusetts to Mich- 
Wind; short root- 
Fields and waste lands; 
(ton viryinicus) , P. 
mes. 
igan, Florida, and 
Texas. 
stocks; plants in 
tufts. 
pastures and mea¬ 
dows. 
Buffalo bur, sand bur 
Yellow; 14 inch; soli- 
Illinois and Colorado to 
Plants rolled by wind; 
Fields; grain and hoed 
(Solatium rostratum), 
A. 
tary. 
Texas. 
seeds in hay and by 
animals. 
crops, wool. 
Bull nettle, horse nettle 
(Solarium carol incuse ), 
P. 
Bur-grass, sand bur 
(Cenchrus carolin- 
ianus), A. 
Purple; 1 inch; soli¬ 
tary. 
Entire United States. 
Plants rolled by wind; 
running roots. 
Everywhere; grain and 
hoed crops, pastures. 
Green; 1-3 inch; bur. 
Maine to Florida and 
westward to Colorado. 
Animals, especially 
sheep. 
Sandy land pastures 
and waste places; 
pastures and wool. 
Chess, cheat (B\romus 
secalinus), A. 
Green; spikelets in 
panicles. 
All grain sections. 
Grain seed, especially 
wheat. 
Everywhere; grain 
fields. 
Chickweed, common 
chickweed (Alsine me¬ 
dia), A. 
White; y s inch; cymes. 
Entire United States. 
Grass and clover seed, 
animals; has a long 
seeding period. 
Meadows, lanws; win¬ 
ter crops. 
Cocklebur, clotbur 
( X ant h i um a merican- 
um), A. 
Green; 1£ inch; head. 
.... do . 
Carried by animals. 
Cultivated fields and 
waste places; hoed 
crops and wool. 
Crab-grass ( Syntheris- 
ma sangiPnale) , A. 
Green; spikes . 
Entire United States, 
especially the South. 
Clover and grass seed, 
hay, animals. 
Cultivated fields, gar¬ 
dens, lawns; hoed 
crops. 
Daisy, oxeye daisy 
White with yellow cen- 
Maine to Virginia and 
Clover seed, hay; 
Pastures, meadows, 
(Ch rysanthemum leu- 
canthemum), P. 
ter; 1 inch; heads. 
Kentucky. 
woody, rather short 
rootstocks, but large¬ 
ly by seed. 
roadsides; hay, pas¬ 
turage. 
