Lexington, Kentucky 40546
      
Nursery Update - A University of Kentucky Cooperative Extension Service update for the Kentucky Nursery Industry
  
By Amy Fulcher, Extension Associate - Nursery Crops
  
University of Kentucky Department of Horticulture
  
Update #3
  
July 2, 2002
  
Pruning:
Timely pruning is essential for a high quality, salable tree. Uniformity in size, shape, and quality are all impacted by pruning.

What to do with lower branches?

• Research has proven and many growers have seen that leaving the lower, temporary branches increases trunk caliper and overall tree growth rate.

• By contributing to caliper development temporary lower branches can help eliminate the need for staking.

• Some lower branches will need to be removed to accommodate herbicide applications. Be especially careful with systemic herbicides.

• Remaining temporary branches may need to be headed back to encourage more rapid growth in permanent branches.

• While dormant pruning, some growers leave temporary branches that are 1/4 inch diameter until summer pruning or the following winter pruning. Specific maximum sizes for temporary branches depend on species, sale size, and time until harvest.

 

 

Photo: Temporary branches left on too long can become a problem. Large pruning wounds take longer to seal, creating entry points for diseases and insects as well as reducing the “salability” and value of the trees.
 

Pruning tall, unbranched liners:

Tall, unbranched liners should be headed back to encourage branch development. This may mean removing several feet to have permanent branches start at about 5'.

See June 13, 2002 update for details.
 
Training the central leader:

Don’t forget to remove the weaker, less straight branch of a double leader, the earlier the better.

For more information: E. Gilman’s An Illustrated Guide to Pruning, 2002; American Standard for Nursery Stock, 1990; and NCSU Leaflet 406 Pruning Field Grown Shade and Flowering Trees, 1996.
   

Insects:
Leafhoppers have now been seen on hawthorns and maples. Monitor populations closely to determine the need to spray. See the June 20, 2002 Update for more leafhopper information.

Sources: U.T. Pub. PB1589 Commercial Insect and Mite Control for Trees, Shrubs, and Flowers.

 

Cultural Problems:
Stakes can damage trunks and contribute to a reduced number of branches on the staked side of the tree. To help alleviate problems with staking:

• Stake only when necessary.

• Remove the stake as soon as possible - hopefully after one season.

• Stake so that the prevailing wind will blow the tree away from the stake, not into it.

• Use a stake taller than the tree to eliminate a rough spot where the top of the stake and the tree come together.

  

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