WEEDS AND THEIR CONTROL 



223 



10. Mowing weeds on roads around fences and in 

 waste places before seeds develop on them. 

 176. How to Kill Perennial Weeds. — Some of our 

 perennial weeds are the most difficult of all to control, 



while some are 

 quite easily 

 eradicated. The 

 tap or fibrous 

 rooted perenni- 

 als can be killed 

 by deep plowing 

 and careful cov- 

 ering of all vege- 

 tation, followed 

 by surface culti- 

 V a t i n. The 

 creeping - rooted 

 ones are not so 

 easily dealt 

 with. One plow- 

 ing is seldom 

 sufficient to kill 

 them and fre- 

 quently several 

 plowings do not 

 succeed in doing 

 so. Three of the 

 common meth- 

 ods employed 'in controlling the creeping-rooted peren- 

 nials are as follow: — 



1. Shallow plowing in the fall and deep plowing the 

 next summer after the weeds have made a fresh 

 start. The first plowing followed by the cold win- 



Fig. 78. — Blue Burr. 

 A typical tap-rooted winter annual or biennial. 



