[Arid_gardener] Re: White sapote dropped leaves

[Dick Gross]

Bcc: vosg members, azcrfg

Michele, there are evidently two of you, Gossage and Smith, clouding the air. That this tree is in a15 gallon pot puts the matter in a slightly different light. Several things could be wrong.

The most common problem I've seen in pots is poor drainage. I always double or triple the number of drainage holes in any size pot and, if possible, nestle all drain openings in the soil beneath the pot so that each has an intimate, wicking contact with the soil inside dropping the water table in the pot all the way to the bottom. I often set a pot in soil or firmly in sod with a hose adjusted to maintain a quarter or half inch of water in the pot for 12 to 24 hours to flush out sal. Fertilize the pot the following day with the amount specified on the fertilizer container.

Depending upon the density of the potting soil and the size of root mass, the water saturation level will only drop to a point where the attraction of the mass is equal to the pull of gravity. That point of equilibrium can occur at any point below about one third of the distance from the upper surface.  Below that level, lacking air, all roots and feeder root hairs there will suffocate. More drainage holes will allow more effective drainage but may not permanently solve the problem. And, drowned roots can't be revived; making recovery slow.

When a water table travels all the way through a pot, it pulls rich, fresh air in behind it. 

Another common problem is channeling. Irrigation may erode channels between the pot wall and soil allowing the water to travel all the way through with little resistance and minimal wetting of the interior that could remain quite dry and, worse, salt-laden.. To correct that condition, I have used a stake or a one inch by four inch slat to pack new soil all around the exterior and filling the new voids with new potting soil. You will take out a few root tips in the process but,  if the trauma causes any significant distress in the plant,  I have not observed it. Getting a proper drink often makes a plant explode with new growth. People react the same way. When you see a person with a big smile on his or her face, you can be reasonable sure she has just had a big glass of cool water.

Many potted plants are hungry. To correct that condition when I suspect it, making sure drainage and proper irrigation are adequate as described above, I dissolve a level teaspoon of any good all-purpose soluble fertilizer in four gallons of water and irrigate with it every time I water that until recovery is obvious. You do not want to be stuck with that regime the rest of your life, however, so let common sense reign. Fertilizer stakes of appropriate dosage and distribution in the pot will also afford constant feeding. You can use the bucket, cleaned-of course, for another purpose like fermenting hops, or something. Just remember that plants have little or no appetite in cold weather. 

Topping a tree, using proper pruning techniques, will force side branching. It is a technique that has been used to control fruit set levels for easier picking. I have done several but can't tell you how with any degree of expertise. I never prune severely, however, until studying the framework for weeks.

Any tree will suddenly shed foliage as a defensive mechanism whenever it senses stress that could be too much or too little water applied in the wrong place, too shallowly or at the wrong time, a sudden change in weather---others.

Many of the plants grown here are on the fringes to their natural habitat and small changes in climate may make them approach dormancy. 

  ----- Original Message ----- 
  From: michelle Smith 
  To: rkgross3 at cox.net ; gossage.michelle at gene.com 
  Sent: Monday, June 26, 2006 8:52 AM
  Subject: Re: White sapote dropped leaves


  Hi Dick, thanks for getting back to me on this.  my white sapote is pretty tall, around 8 feet tall. I would like to take a picture of it and show it to you. I will try to do that in the next few weeks.  The tree is in a 15 gallon pot. I won't have space to move it into the ground until next year.  The tree seems to be doing ok except for the recent sudden leaf drop. Thanks a bunch for the info on  drip line.  I"m hoping to trim the tree down to its lowest branch but wanted to ask you for your advice on if this would work for Sapotes? I would like it to grow busier and wider rather than taller. By trimming down to its lowest branch, ~ 6 feet up the trunk would this signal the tree to grow more side branches ?  Again, I will send you pictures when I can.  I had been watering my tree well while the weather was hot but I missed two days at temps of ~90 degrees. I though it would be fine since the soil had already been soaked the previous two days.  I've since watered it again yesterday but only lightly. The leaves remaining on the tree look fine, no wiliting or dropping. I'll let you know how it fares the next few days. 

  Thanks

  Michelle



----------------------------------------------------------------------------
    From: "Dick Gross" <rkgross3 at cox.net>
    To: "Michelle Gossage" <gossage.michelle at gene.com>
    CC: "file DickGross" <rkgross3 at cox.net>
    Subject: Re: White sapote dropped leaves
    Date: Fri, 23 Jun 2006 18:05:32 -0700


    Michelle, I have an adult White Sapote McDill,  in Phoenix Arizona where it has been about 109 degrees. I see none of those symptoms in my tree nor in another we have in our demonstration garden at the University of Arizona Maricopa Cooperative Extension also surviving in 110 to 113 degree heat.

    I would be surprised if your tree is suffering from a disease. This species is quite disease resistant with no natural enemies I am aware of in these areas. I am guesing from your meager discription of the sympyoms that your tree is thirsty.

    Make a line in the soil with a stick outlining the outer reaches of the foliage, This is the drip line. All  feeder roots are confined in a zone a couple of feet inside and outside that line. Make a shallow trench all around the tree with that drip line being the approximate middle of it.

    Put a garden hose in the trench and adjust the flow until you have at least a half inch head of water all the way around the tree. Do not fertilize at this time. Run the water until you have soaked the ground at least three feet deep. You determine that depth with a probe made from 1/4th inch brass rod 3 feet long, one end of which you have filed a dull point and, for the other, fashioned a 6 inch handle by drilling a hole in a piece of an old, discarded shovel handle. Yoy get the brass rod at any hardware. If you have other trees, hang on to that rod. It will become your most valuable tool.

    When you can sink that rod to the hilt several places around the drip line, shut off the water. Depending upon the soil texture, it may take from four to twenty four hours to get that depth but adjust the flow to keep a half inch in the trench until you do.

    Do not water again until the surface is quite dry two to three inches below the surface. A three or four inch layer of mulch will reduce surface evaporation that will also prevent the deposition of salt concentrated in the shallow root zone by evaporation. 

    If your tree is confined in a small area or between houses, use your best imagination to try to irrigate as described above.

    Let us know how your tree fares.

    Dick Gross, Secretary/Editor
    Arizona Rare Fruit Growers.
    Bcc: info at crfg; vosg; axcrfg





    -- Original Message ----- 
      From: Michelle Gossage 
      To: info at crfg.org 
      Sent: Friday, June 23, 2006 4:08 PM
      Subject: White sapote dropped leaves


      Hi CRFG. It's been pretty hot lately around 95 degrees this week but I have been giving my white sapote plenty of water. Its located between the alley way of two houses, gets indirect filtere sun. The leaves look sick, like really wilted and yellow then drop. I think there is a diseas but don't know what could cause all this leaf wilt and drop. Any ideas? What should I treat with. Could it be that a few hot days would cause this even with watering or is it more likely an infection of some kind?
      Thanks very much 
      Michelle 


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