202 IOWA DEPARTMENT OF AGRICULTURE 
can be given it is to turn it into pasture. Cattle, sheep, and hogs are 
very effective in keeping the weed down. One correspondent thinks that 
four years in pasture will keep it in check. The plowing should he 
thorough, discing, and harrowing, or hoeing as often as the weeds make 
their appearance. Millet, sorghum, and buckwheat are effective in keep- 
ing the weed down. 
Milkweed. Milkweed can be treated very much like the Morning Glory, 
and apparently there is nothing better for its treatment than to put it in 
pasture. The Milkweeds growing in a pasture or meadow are usually 
small. The plant has a wonderful capacity for spreading. The roots, 
at times, may be found fourteen feet away from the parent plant and at 
numerous points they produce new shoots. A rotation recommended for 
Milkweed is as follows: oats one year, clover one year, corn two years, 
then pasture, and generally after the second year it is not troublesome 
in the pasture. 
Horse Nettle. No other weed is so troublesome with the exception of 
Canada Thistle, as is the Horse Nettle. The spiny character of its stem 
makes it particularly objectionable and moreover the plant is poisonous. 
It is a deep rooted perennial, extending from two to four feet down into 
the soil and every severed root throws up a new shoot. The best method 
for exterminating is to give thorough cultivation, this can be shallow, 
the roots being exposed to the sun and allowed to dry. If in a field of 
oats or wheat, it should be plowed as soon as the grain is removed, then 
disced and harrowed, and this kept up until frost. The field should not 
be cultivated with corn unless it can be followed with the hoe, as the 
cultivator is sure to spread the weed over the field. 
Dropseed Grass. Dropseed Grass may be exterminated by ordinary 
cultivation. If it is abundant in a field it should be plowed after the 
grain is removed, then disced and harrowed. The roots of this plant 
are clustered. These roots are readily destroyed upon exposure to the 
sun. 
SOME ANNUAL WEEDS. 
Gocklehur. Cocklebur is a serious menace to cultivated crops in many 
parts of the state. The seed habit of this plant differs very materially 
from any of the other annual weeds. Each bur contains two seeds, one 
seed germinates one year and the other the second year, so that no 
matter how careful you are in trying to keep the field clean for one 
season you cannot exerminate the weed in a single season. If the cockle- 
burs occur in corn fields the weeds should be removed with the cultivator 
as much as possible and this should be followed with a hoe but in the 
majority of cases it is possible if taken in time to remove these weeds 
without the hoe. The field should then be sown the next season with a 
small grain crop, like barley or rye or oats and then brought into a 
clover meadow and finally into timothy and blue grass. How long the 
seeds of cocklebur retain their vitality is not definitely known but it is 
certain that v/here this kind of rotation has been followed that the cockle- 
bur is not a troublesome weed. 
