Ironite on Dogwoods

Another Dear Reader question!  Can I use Ironite on dogwoods?

Answer:  A technical yes, but...

If your dogwood is showing signs of iron deficiency like widespread yellow leaves in spring and summer, iron deficiency is one possible problem (magnesium shortages, nitrogen shortages, too much or too little water, or half a thousand other things are also possibilities).

First, get a soil test (I say that a lot).  Pay attention to two things:  soil pH and iron levels.  If iron is OK but pH is high, iron might help temporarily but you're likely to return to the original conditions pretty quickly.  If iron is low and pH is under 7.0, iron deficiency is more likely.

In the latter case, Ironite might help.  However, it's a rather expensive way of adding limited iron without otherwise doing much for your tree.  In this case, and given the small area that trees tend to encompass, I'd recommend using Milorganite at bag rate under the drip line of the tree.  It contains slightly more iron, plus helps feed the tree.

In the former case where your pH is over 7.0, Milorganite will help by adding some organic material to the soil.  Iron likes to bind to organic matter, and releases from it more easily than from the soil, so over several years of monthly use you should notice a steady improvement in your tree.

In most cases, I don't recommend trying to reduce your pH if it's very high (7.8 or above).  This is more common in lower rainfall areas of the nation, and quite rare where I live.  While adding sulfur might help a bit, sulfur is much more effective if dug into the soil and in soils that don't have free lime. Very high pH with very high calcium levels is an indication of free lime.