Re: Companion Plants for Roses

Catherine, et al:
 
This is not the latest "theory".  In the early 1970s, Dr. Carl Whitcomb, a researcher at Oklahoma State University, disproved the oft-repeated advice of amending planting holes. In controlled studies using percentages of different amendments (up to 40%), roots of ornamental trees and shrubs were consistently larger in unamended soils. The amendments seemed to encourage roots to stay in the vicinity of their planting holes and not grow out into the unamended soil, leading to stunted root systems. Whitcomb concluded that it's best to let the roots begin to grow in the nativ soil right away and to use organic matter on the surface as a mulch, rather than mixing it with the soil. If a tree isn't suited to native soil, you are better off growing it in a container than trying to change the soil with amendments.
 
The research was duplicated at the University of Georgia and various UC colleges with the same findings.
 
But, amending aside, you SHOULD dig a WIDE and shallow hole for planting.  Not the "2x wide and 2x deep" wisdom of nursery old-timers (of which I are one).  The hole should be dug up to 3 times as wide and the native soil removed and broken up.  The bottom of the hole should be dug just deep enough to allow one to scratch up the hole bottom and give one room to adjust planting height.
 
Another myth is using gypsum to somehow break up clay soil.  Gypsum works in a chemical/ionic fashion to flocculate (I love that word) another kind of "heavy soil" -- sodic (or alkali) soils.  The calcium ions in the gypsum replace the sodium ions in the soil and allows water to wash the sodium away. It's the sodium ions that cause the soil particles to bind together, hence creating "heavy" soil.  Typical clay soils of California are not sodic/alkali and gypsum does nothing to change their structure.
 
I do not doubt, Catherine, that your experience has paid off.  I would allow that more personal attention to your planting technique (whatever it is) has given you better results.

I also doubt that the pratice of soil amending and using gypsum will subside as long as sales of amendments and gypsum are encouraged.
 
Joe
 
Catherine Ratner <catherineratner@earthlink.net> wrote:

I know that the latest theory does not favor amending soil in the planting
holes, but this theory does not accord with my experience. I have tried
many native plants on my north-facing slope which is in full sun at high
summer, full sodden shade in winter. If I try to plop a gallon plant, which
has been grown in a mix of sand and shavings, into a hole in my exceedingly
tight black adobe, the hole tends to fill with water and the discouraged,
pampered roots are not able to make their way into the soil. If I dig a
wide hole, amend the soil with gypsum and the light mix I shake off the
roots of the plants, they can often make it. This is the only way I have
been able to establish Salvia 'Winifred Gilman', for example. The plants
are not totally inappropriate for the site; they just need a little help at
first. If they become chlorotic as adults, I jerk them out.

Cathy, Sunset zone 23, US zone 10.

> From: Joe Seals
> Reply-To: gardenguru@yahoo.com
> Date: Fri, 14 Jan 2005 09:58:39 -0800 (PST)
> To: gardenwithkitties@hotmail.com, medit-plants@ucdavis.edu
> Subject: Re: Companion Plants for Roses
>
> Robin:
>
> No debate. I'm with you almost across the board.


> The one minor area where I disagree is where you suggest amending soils to
> better grow roses (and other plants?). I believe, first, that we should all
> plant the right plant in the right place. That includes selecting plants for
> your native soil and climate. Roses aren't meant for light, dry soils.
> Second, I believe that amending planting holes is a short term answer that
> research has shown to be the wrong way to plant. So much for this universal
> practice. These are the bigger principles of "natural gardening".
>
> Joe



Joe Seals
Santa Maria, California --
where the weather is always perfect
and my NEW garden will soon be blooming and full of birds and butterflies

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