LUTHER BURBANK 



where the life of the plant is protected until spring. 

 Many perennials have underground stems which 

 are sent out in all directions. From each 

 node a new plant may grow under the proper con- 

 ditions. 



It is obvious that such weeds are most difficult 

 to destroy because, although they may be pre- 

 vented from bearing seeds, they distribute them- 

 selves over large areas. 



The handling of annual weeds is summed up 

 briefly in one sentence: Prevent the production 

 and the introduction of seeds. 



But with perennials not only must the introduc- 

 tion and production of seeds be prevented, but the 

 entire plant must be uprooted and destroyed. 



When perennial weeds have taken possession 

 of an area of land, they may generally be brought 

 under control by thorough cultivation during one 

 or two seasons. This often means that one or 

 more crops must be sacrificed. Every weed on the 

 entire area must be destroyed as soon as and with 

 some kinds before it appears above the surface. 



The vitality and food provided by perennials 

 in most cases does not keep the plant alive more 

 than one season. The plant depends upon its store 

 of food being replenished by another growth each 

 season. If the leaves cannot develop above the 

 ground, so that raw food collected by the roots 



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