296 



WEEDS 



harrowing, exposes the rootstocks to the winter frost. 

 This will kill most of them. There should follow in the 

 spring, cultivation thorough enough to keep leaves from 

 appearing above the ground. Without leaves (the breath- 

 ing organs) the roots 

 must soon die. In the 

 summer, hemp, millet. 



Two KINDS OF PIGWEED. 



CANADA THISTLE. 

 Note length of rootstock. 



or buckwheat may be sown as a smothering crop to com- 

 plete the eradication. 



b. Scattered plants, or small patches, may be covered 

 with tar paper or other heavy paper. The paper excludes 

 the sunlight. Or the plants may be kept cut close with 



