[Arid_gardener] Re: Failing Austrailian Orange tree

[Dick]

Unloading foliage is the first sign that a citrus (read any tree) is not happy in its environment.  The first thing that I look at is how and where the tree is being irrigated. Most, or all. of the feeder roots that can take in water and neutrients are in a two or three-foot wide band around the tree with the dripline, ideally, in the middle of the strip. Regardless of how old or large the tree, it must be fed where it has feeder roots or you are just spitting in the wind. It would be as ineffective as you trying to take nutrient through your finger tips. The first signs of mal-nourishment might be a loss of hair with your fingernails falling off; I'm guessing, of course. An organism will only retain the appendages it can maintain--shedding what it cannot sustain.

Citrus must be irrigated, and fed, at the dripline to a depth of at least three feet. Deep rooted trees are not as reactive to subtle changes in climate and nutrient. In a well populated yard, feeder roots may reach out to distant beds for food and water but feeder roots will not cross dry soil to reach them.

The first thing I would do is deep water at the drip line. If you don't have a shallow trench there, make a broad one that will hold ar least a half inch head of water. Put a hose end trickling in the trench to hold that head of water until you can sink a probe three feet in the trench several places around the drip line.

Wait a week or ten days and do the same thing with the correct amount of citrus fertilizer distributed in the trench. But, hold on! Your climates are reversed in Australia. Run this advice by your professional nurseryman to adapt it to your geographic variences. 

Twenty years old is near middle-age for a citrus variety, but, depending on the kind of stress the tree has been under, physiologically, it could be much older. 

It is worth trying to resurrect your tree and such attempts with citrus are often spectacular. Let us know how this works out. If any of my suggestiona are unclear, don't hesitate to raise questions. This is citrus country and experts here abound. Yours truely is a mere amateur with four healthy trees all over 40 years old in a somewhat hostile desert environment.

Dick Gross, Master Gardener Volunteer
University of Arizona Maricopa County
Cooperative Extension. 
  ----- Original Message ----- 
  From: david 
  To: Arid_gardener at Ag.arizona.edu 
  Sent: Saturday, September 01, 2007 12:51 PM
  Subject: [Arid_gardener] (no subject)


  I live in SE Australia. My orange tree is over 20 years old and dropping its leaves.Is it dying?


------------------------------------------------------------------------------


  _______________________________________________
  Arid_gardener mailing list
  Arid_gardener at CALS.arizona.edu
  http://CALS.arizona.edu/mailman2/listinfo/arid_gardener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://CALS.arizona.edu/pipermail/arid_gardener/attachments/20070902/59eb0245/attachment.html