Re: Japanese Iris & pH--Test your soil.
- To: Multiple recipients of list <i*@rt66.com>
- Subject: Re: Japanese Iris & pH--Test your soil.
- From: "* a* C* W* <c*@cache.net>
- Date: Mon, 3 Mar 1997 19:18:24 -0700 (MST)
On the question of whether or not lime (calcium oxide) is directly toxic to
Japanese Iris and other acidophilic plants or if the adverse effect results
from lime's ability to raise soil pH, I think it is the latter (raising the
pH) that is critical. In a high pH environment these plants lack the
ability to absorb iron, even though it may be abundant in the soil. So, as
I understand it, their problems arise from iron deficiency and not calcium
toxicity.
R. Dennis Hager writes (3 Mar 97):
> On the other hand, George Bush told me that he at one time routinely
> acidified soil for Japanese iris. He once lost some Japs because he had
> gotten the pH too low.
In his book on Japanese Iris, Currier McEwen notes that in one Missouri
garden when pH was lowered to 4.5 some JIs were lost, and when it was
lowered to 4.0 all JI plants were lost or seriusly affected. So, pH can be
too low for JIs, as well as too high. This makes Dennis's advice about the
importance of soil testing (which I deleted above) doubly significant.
Jeff Walters in northern Utah (Zone 4)
cwalters@cache.net
"This is the Place" - pH 6.5 to 6.7 - a bit high for JI
