WEEDS AND GRASSES. 261 
plow the alfalfa in regular course of rotation any 
way. Later on I will tell of what good may come 
of using blue grass and alfalfa together. 
Plantains are a serious annoyance in alfalfa fields. 
Drain the land where they appear, enrich, and if need 
be lime, re-sow and plantains will be a thing of the 
past. Canada thistles have been mentioned; alfalfa 
is the best known eradicator of these. 
Sweet clover is often mentioned as a weed in al- 
falfa fields. It is usually introduced through the 
presence of sweet clover seeds in the alfalfa seed. 
Often the unfortunate seedsman is blamed for this. 
Sweet clover is not often intentionally added to al- 
falfa seed. Sometimes, in fact, melilotus seed sells 
higher than alfalfa seed. The seeds are nearly ex- 
actly alike; only an expert can tell them apart, and 
no machine in the world would separate them. The 
sweet clover seeds get in when the alfalfa seed is 
harvested, through accidental. admixture in the west- 
ern fields, where it quite frequently grows along the 
edges of the fields. A seedsman who is quite care- 
ful to get the best western seed is very likely to sell 
a small amount of sweet clover seed, quite against 
his desire. 
Sweet clover in the alfalfa, however, is not at alla 
serious pest. At first it makes its bravest showing; 
the frequent mowings cause it to disappear and 
being a biennial it is soon gone with no harm done. 
Russian thistle comes in new seedings of alfalfa 
from western sources. This promptly disappears 
with mowing. Docks in alfalfa will probably persist 
