284 LUTHER BURBANK 



Annual weeds reproduce themselves by seeds 

 which mature each season, usually in great abun- 

 dance. Perennials, in cold climates, although 

 most of them produce seeds, also perpetuate 

 themselves by storing food and living matter 

 under the ground 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 conditions. 



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 the 

 perennials not only must the introduction 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 

 wholly under the control by thorough weekly 

 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. 



