On Thu, 19 Jul 2007 15:29:04 -0400, Stephen Henning
wrote:

Persephone wrote:

On Sat, 14 Jul 2007 18:12:21 -0700, Persephone wrote:

I have an azalea in a large pot on the E. side of the house
(So. Calif coastal), that has turned chlorotic. I gave it
iron twice, but has had no effect; leaves still have that
tell-tale appearance.

FWIW, here's the reply I received from my local nursery:
Ironite is the right way to go, but if the roots do not get enough
oxygen to enable the plant to take in the trace elements (Iron,Zinc,
Manganese etc) it will not help. What I mean with enough Oxygen, is
that Azaleas could easily be planted too deep - they like to have the
root ball be exposed, so I would recommend scraping the top layer away
from the trunk and not keeping the soil soaked. A liquid fertilizer
sprayed on the leaves such as soil acidifier should rectify the
problem faster than if the nutrients were to be absorbed by the roots
and transferred to the leaves.

There is some truth to what they are saying, but:

1) if the soil is not acidic, iron won't help. The soil must be acidic.
The soil must be made acidic. Powdered sulfur will do this.

The soil in this area is adobe (basic), but the people before me
mulched regularly, as have I, so I suspectthat over many decades of
modification the PH has become either acidic, or at least neutral. I
should have it tested some time just out of curiousity, though I don't
usually have problems like this.

2) if the soil is deficient in potassium, calcium, or magnesium it will
show the same symptoms but the iron won't help. Potash of Sulfur
(K2SO4), Gypsum (CaSO4), and Epsom salts (MgSO4) will address these
respectively if used in moderation.

3) if you have poor drainage the scraping the top layer of soil will
cause puddling and make the problem worse. Using a raised bed with good
acidic soil will address this problem.

Good drainage in that large pot. Water doesn't puddle.

4) if it isn't getting enough oxygen, it can be poor drainage and/or
being planted too deeply. Using a raised bed and not planting any
deeper than it was originally when purchased will solve both problems.

I've scraped away some soil from the trunk; have refrained from
over-watering, and will pick up some powdered sulfur.

Unfortunately, most stores feed the customers desire to buy a product to
pour on the problem and solve it. That doesn't always work.

That's probably true, but the email from the nursery was not pushy.
I already have some Miracle-Gro; it probably won't kill the plant
to get a moderate application.

Stay tuned!

Persephone