[Arid_gardener] Question from Home-Hort WWW page

[Dick]

Bruce. I have lived in this valley since 1968 and have never seen what I 
learned as a geology major was calcium  carbonate (caliche).  These are 
deposits, usually ancient river gravel beds, bound together by calcium 
carbonate to form a strata--an inch or two to several feet thick, that are 
totally impervious to water but a clay binding agent is just as bad, in my 
opinion. I have dug shallow footings for houses where filling the trench 
with water for a week would only soak in a strata a quarter inch. In one 
footing, the inspector gave me a pass on a depth of six inches rather 12 
annuling the necessity of hiring a jack hammer. But, if planting a tree or 
bush with deep rooting characteristics in a hole as described, the home 
owner is facing a mild disaster or, at best, a half dead tree. Regardless of 
the bonding agent, if irrigation water won't penetrate it, water will puddle 
in the root zone and drown the tree. Feeder roots will not survive in water 
or any medium that excludes a lot of air space between soil particles.

Clay-bound particles are as bad or worse but, with either, what we end up 
with is a layer of natural concrete that will never go away or "melt" 
unless, or maybe, you live to a thousand years old.

Before you plant a tree, test the drainage properties as follows. Dig a 
hole15 inches deep, fill it with water and let it set over night. If the 
water is gone by the following morning, you probably have no problem but 
fill it again and again to determine its drainage characteristics that can 
guide you with your method of irrigation.

If your tree appears to be setting in or on such material, dig one or more 
holes any way you can through the strata and fill the void with rounded 
river rock. Crushed rock will readily clog again and your tree will be 
setting in a mud puddle.

Many trees in the area are properly irrigated when the trees are junenile 
but as the drip line is extended, the irrigation trench is left way within 
the drip line where there are no feeder roots that cannot penetrate dry soil 
anyway.  I have several healthy heavy bearing citrus that have never been 
irrigated inside the dripline trench unless it has rained.  I irrigate in 
the drip zone until I can sink a soil probe easily about 36 inches into the 
soil in several places around the tree. I do not irrigate again until I 
scratch 3 inches into the surface in the trench and find dry soil at least 
three inches deep. A tree properly irrigated will never suffer water stress 
nor blow over if anchored by a deep root system..

A tree's roots will follow the water table to a depth that anchors it 
against wind.  and outward If this leaves questions unanawered, don' 
hesitate to inquite further.

Dick Gross, Master Gardener Volunteer
University of Arizona Maricopa County
Cooperative Extension

----- Original Message ----- 
From: "Tyler Storey" <tyler at tylerstorey.com>
To: <Bruce.Chandler at tmcaz.com>; <arid_gardener at Ag.arizona.edu>
Sent: Friday, April 18, 2008 1:26 PM
Subject: RE: [Arid_gardener] Question from Home-Hort WWW page


> Hi Bruce,
> You're entirely on the right track in wanting to be certain that the trees
> are planted properly to prevent future problems.  Ideally, the trees 
> should
> be planted in hole that is two to three times the width of the root-ball,
> and only as deep as the root-ball, no deeper.  The exception to the depth
> would be if you have a known caliche layer, in which case you do want to
> have it at least fractured, to facilitate drainage.
>
> Digging the hole two to three times as wide as the root-ball, and then
> backfilling with no soil amendments help to make certain that the tree 
> will
> have loosened soil in which to put our its initial root growth.
>
> Water also plays a big role in trees that blow down after five years in 
> the
> ground.  Your trees should always be watered widely -- to the drip line of
> the canopy and beyond -- and deeply, to a depth of about three feet every
> time you water.  Yes, three feet, even for desert-adapted trees. Deep, 
> wide,
> and infrequent water will help to make certain they develop a strong root
> structure.
>
> You don't mention the type of trees that blew down, but that plays a role 
> as
> well.  Non-native mesquites are in particular prone to blowing down, 
> whereas
> our native mesquites and other native trees -- properly planted and 
> watered
> -- are less susceptible to wind damage.
>
> I hope this helps,
> Tyler
>
> tyler at tylerstorey.com
> http://tylerstorey.com
> 602-738-2978
>
> -----Original Message-----
> From: arid_gardener-bounces at CALS.arizona.edu
> [mailto:arid_gardener-bounces at CALS.arizona.edu] On Behalf Of
> Bruce.Chandler at tmcaz.com
> Sent: Thursday, April 17, 2008 11:15 AM
> To: arid_gardener at Ag.arizona.edu
> Subject: [Arid_gardener] Question from Home-Hort WWW page
>
> Bruce
> 85658
> Bruce.Chandler at tmcaz.com
>
> Hello,
>
> My wife has hired landscapers to native plant trees.  They built a box 
> area
> about 10 feet by 10 feet out of cemet blocks--it is nice, but I told my 
> wife
> to be sure and tell them to break up the cliliche (sp) before she has them
> plant the tree, otherwise the tree won't grow properly in the space.   It 
> is
> very hard and difficult to dig in our yard, and I know that they won't do 
> it
> unless we insist.   Other trees in our yard, in fact the entire 
> neighborhood
> have blow over--trees that were five years old--because the landscapers 
> just
> seem to have made a small hole (ground is very very hard) and roots have
> fanned out and not in the ground.  Can you comment on this please?  I'm
> afraid that they trees will not take proper root.
>
> Cheers!
>
> Bruce
>
>
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