D 



REES are an indispensable part of a pleasing 

 landscape. Their establishment and maintenance concern 

 homeowners, arborists, municipal foresters, and those 

 responsible for the grounds in parks and around public and 

 private institutions and commercial buildings. The care of 

 trees involves several cultural practices, including fertiliza- 

 tion, about which this circular gives basic information. 

 A section on watering is also included because the soil 

 solution is the major, if not the only, vehicle for moving 

 nutrients from soil colloids and organic matter to the roots 

 of trees. 



Why fertilize? 



The correct and timely application of fertilizer benefits most 

 trees. Newly established trees grow more rapidly following 

 fertilization with a nutrient or a combination of nutrients 

 that occur naturally in limited amounts in soil: increased leaf 

 size, increased twig growth, and more rapid increase in 

 height. Slow-growing tree species, many of which have 

 desirable characteristics, can be stimulated to grow faster by 

 fertilization and can thereby be used in situations where slow 

 growth is undesirable. 



Stunted leaves and the early loss of leaves often indicate 

 nutrient deficiencies in the soil. Leaf color, especially pale 

 green or yellow, also indicates deficiencies as do leaves with 

 mottled patterns between the veins or leaves with dead spots. 

 The leaves of many trees become a darker green following 

 fertilization, and this change of color makes them more 

 attractive. 



fertilizing also helps to maintain mature trees in a vigorous 

 growing condition. A vigorously growing tree is less 

 susceptible to certain diseases and to insect pests than is a 

 less vigorous tree. Canker-causing fungi occur more 

 commonly on weakened trees, and many noninfectious tree 

 diseases develop when soil nutrients and moisture are 



