WEEDS 



339 



readily transported seeds, such as goldenrod, thistles, prickly 

 lettuce, and milkweeds, to seed all adjoining parts of the farm. 



Many useful plants and still more harmful ones spread by 

 vegetative means so as to overrun neighboring ground. In 

 this way a blackberry patch may spread by the root so as to 

 become a nuisance, and black raspberry bushes will travel by 

 means of their long root- 

 ing branches (fig. 72) so 

 as to cover much ground. 

 Couch grass, or quack 

 grass (fig. 245), growing 

 beside a cultivated field 

 or garden will soon spread 

 into the cultivated soil 

 by means of its vigorous 

 rootstocks. 



Methods of destroying 

 weeds cannot be treated 

 in detail in a textbook 

 on botany, though a few 

 words may be given to 

 the subject. Weeds which 

 have gone to seed should 

 not be plowed or spaded 

 under, but should be 

 burned when dry. It will 

 be found well worth while 

 to rake away from fences 

 and burn all accumulations of tumbleweeds. Wild mustard, 

 which is a very troublesome weed in fields of the small grains, 

 is readily killed by spraying with a solution of copper sulphate 

 or iron sulphate. Weedy lawns are sometimes improved by 

 very careful salting, which does not injure the grass. Gravel 

 walks may be cleared of weeds by watering them with a highly 

 poisonous solution of sodium arsenate or of crude carbolic acid. 

 Rotation of crops (that is, following the crop of one year by a 



FIG. 246. Wild oats, a grass belonging to 

 the same genus as the cultivated oat 



It is an extremely troublesome weed, espe- 

 cially in fields of the small grains. After 

 " Farm Weeds of Canada " 



