WEEDS 



183 



tion of seeds should be prevented by cutting the tops 

 down for a number of years. Even if the growth of seed 

 is prevented, there is still more work to be done to rid the 

 land of the roots of these long-lived, robbers. 



The vigorous growth and abundant formation of seed 

 by some weeds are shown in Figs. 121 and 122. 



Killing perennial weeds. Weeds that come up year 

 after year from the roots are usually not easy to kill. 



FIG. 121. MULLEIN 



FIG. 122. NARROW-LEAVED DOCK 



Plowing them with a sharp plow sometimes destroys them 

 if the roots are all brought to the surface and thus dried. 

 This is one of the easiest ways to kill Bermuda grass. Shal- 

 low plowing is best for killing this grass because the shal- 

 low furrow-slice dries out more completely than a thicker 

 layer of upturned soil. Any plant is more easily killed 

 late in its growing season, for then it cannot so easily 



