CHAPTER XXVII 



CONTROL OF WEEDS 



, The noxious weeds are of three main types. (1) Those which 

 grow from seed each year and die in the winter; these are called 

 annuals. Examples: purslain (Fig. 244), pig weed, rag weed, etc. 

 (2) Those which grow continually year after year from the same 

 underground parts, but may die to the ground each year; these are 

 called perennial herbs. Examples: dock, Canada thistle, quack 

 grass, Johnson grass, plantain (Fig. 245), dandelion, etc. (3) Those 

 which grow one year from seeds and store nourishment in the 

 underground parts and die to the ground the first winter. During 

 the second growing season they make a rapid growth from the 

 nourishment in the underground parts and produce flowers and 

 seeds, after which they die completely the second winter, the only 

 live part remaining being the seeds. These are called biennials. 

 Examples : burdock, wild carrot, and many others. 



Relation of Type to Methods of Control. — As annual weeds die 

 each year it is not difficult to eradicate them. All that is necessary 

 is to keep them from going to seed. In that case they will all be 

 dead by winter. They spread each year by seed, and if the seeds 

 are allowed to form they will not be injured by winter. They will 

 spread, and the weeds will become more numerous and more widely 

 dispersed each year. 



Annual weeds are usually found in cultivated fields where the 

 seeds find a good seed bed for germination. Gardens are much 

 more troubled with annual weeds than with perennials. 



Perennials and biennials are more common along fence rows, 

 road sides and in orchards or other places that are not regularly 

 cultivated. 



Such weeds store nourishment in the underground parts and 

 live from year to year if their roots are not destroyed by tillage. 

 The most successful way of destroying perennials is to plow and 

 cultivate thoroughly. Nearly all perennials are easily destroyed 

 by this method. There are a 'few with runners or rootstock that 

 are difficult to cut with tillage implements; among them may be 

 mentioned quack grass, Johnson grass (Fig. 246), Canada thistle 

 and Bermuda grass. Weeds of the wild onion type which have 



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