Tree planting

A new tree and shrub planting method is finally catching on somewhat in the landscapes. Resistance to the method rallies from a couple different quatrters. Those who decide not to change or even try something different and those saying its too expensive lead the enertia against the method.

The method and the supporting research have been around for years. The late Dr. Jimmy Tipton lead the way getting the word out in the southwest.

The reasons for being a preferred planting method lie with the botanical fact that. Roots also extend out much further than the 'drip line' or the edge of the plant's canopy and most active and absorbing tree and shrub roots exist in the upper two to three feet of soil. It should make sense if you consider that in nature water comes from rain, the richest soil is near the surface and roots need oxygen to grow and abosorb water/nutrients and the deeper in the soil the lower the oxygen levels.

Granted some plants develop tap roots or lateral sinker roots. Even with these plants most of the water and nutrients get absorbed by the shallow roots.

The method directs thus:

1. Dig the hole no deeper than the soil in the nursery container.

2. Dig the hole or loosen the soil three to five wider than the container diameter.

3. Add no organic amendments to the soil (don't get excited yet - you'll apply the organic matterial late and more usefully.)

4. Backfill the soil and set entire arear once to settle the soil.

5. Apply a four to six inch layer or organic material on top of the soil as a cooling and insuating mulch for the roots.

This method has been tested under every soil type, every part of the country and every condition imagineable with consistantly positive results. Plantings all over the state show it works.

From a plant health perspective this insures that the plant trunk will not sink and become vulnerable to basal trunk rotting. This problem ranks high on tree disease lists in the low desert.

From a logic perspective the old method said dig a deep hole. Then put the soil you just dug out back into the hole so the hole is no deeper than the container. Oh yes, also this soil put back in should be compacted soil the plant will not sink after planting. Why dig it any deeper to begin with?

Are the skeptics going to change? Probably not. The nonchangers will contnue status quo. The naysayers claiming the expense are correct. The old adage of "plant a $5 tree in a $50 hole" should explain it. This method loosens more soil and takes more mulch than before. It will cost more but aren't your plants worth it?

Written by Terry Mikel, College of Agriculture and Life Sciences, the University of Arizona, 602-470-8086.
Material originally appeared in Arizona Republic
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