THE WEED NUISANCE 329 



most annual weeds and some perennials. One can set 

 the mower so high that it will not especially injure the 

 grass. Ironweeds (Vernonia novel) or acensis) are trouble- 

 some perennials. After 40 years of more or less persist- 

 ent struggle with them in one of our pastures they are 

 still present, though much reduced. Mowing off just 

 as they come into bloom, and feeding with .sheep which 

 eat off their leaves when young and tender, seem the 

 available remedies. Ironweed comes in the best soil 

 and troubles over a very wide area; its roots are very 

 large and strong. Mulleins are biennials and are de- 

 stroyed by pulling or mowing just as they bloom. Coarse 

 rank weeds such as horseweeds (Ambrosia trifida) and 

 jimpson (Stramonium) are easily destroyed by mowing; 

 in fact, the mowing machine is a most effective ally of 

 the pastoralist. Some weeds are destroyed by sprink- 

 ling repeatedly with strong brine. . The nettle is thus 

 affected, as also is poison ivy (Rhus) and the horse net- 

 tle (Solanum Carolinense). This latter weed is a dis- 

 tressing one, and is now invading all of the central 

 states. It has not one use nor redeeming feature, nor, 

 after it is established all over one's farm, can it ever be 

 eradicated; so it should be fought to a finish at the out- 

 set of its invasion. One of the most persistent and 

 troublesome weeds is spearmint. Mowing twice during 

 the season greatly injures it, and will in time perhaps 

 destroy it. Hoarhound should be pulled by hand as soon 

 as it appears. Canada thistles; who can in a sentence 

 dispose of them? In England farmers content them- 

 selves with cutting them down once or twice a year to 

 prevent their seeding. They will continue, however, 



