Evergreen/rhododendron & azalea fertilizer.

I would agree with bboy unless you already apply a fertilizer. The best time is February or June for a light feeding. However, when I visited with a local nursery about some pale colors on shrubs in my yard (Bellingham) he told me to add a little Dr Iron. That was last year. This year they seemed to be better.

Iron deficiency is supposed to be associated with alkalinity so I have to wonder how often applications of iron are really what is called for in this area. The usual deficiency in cultivated (gardened or landscaped) soils here is one of nitrogen. When you clear the native growth away a lot of the nutrients go with it. If you don't have a deliberate system for making up for this in operation your soil often becomes depleted - depending on what kind of soil you have.

I would have to agree. Nitrogen is lacking usually here more than iron. Soil structure and the amount of organic matter in the soil is my primary concern when it comes to plant health.
And drainage, of course.
Mike

There are some limestone deposits in the Bellingham area, if a party happened to live on one of these maybe iron additions might actually be appropriate. If the limestone was actually tying up iron, not necessarily the case every time it is present.

Most of the time when I encounter mention of iron being applied here or see it for sale I think it is not needed.

Local extension services tend to have differing opinions from the above :-) Iron deficiencies are not always tied to alkaline soil conditions - in fact, soils that are only mildly acidic (a relatively common PNW situation) tend to bind iron, making it unavailable for plant uptake. That's why fertilizers forumlated for acid lovers - rhodies & azaleas, camellias, blueberries, etc., all tend to have a significant iron component. Conversely, highly acidic soils have the same effect re: iron availability but through antagonism with other nutrients, typically aluminum and manganese.

As to how effective iron supplementation may be, it only takes a quick application of chelated iron (or Miracid) and the resultant almost instant "greening up" of the foliage of virtually any pale broadleaved evergreen for justification of its use.

I thought those products (ones like Miracid) had a lot of iron because they were being used by people trying to grow acid soil plants in alkaline ones. Gardenias in California, for instance.