Question: What other landscape shrubs benefit from an application of iron chelate? I know bottlebrush and photinia. Others?
That’s a good question. There are so many, but for the most part, those plants that originate from desert environments usually do not need it. Conversely, those that come from climates that are not a desert frequently will.
For instance, Texas ranger seldom, if ever, needs it. Likewise, those that are sold as truly desert plants will not. There would be literally hundreds that we could list.
There are some that are notorious for yellowing and needing iron, particularly if they are put into rock-type desert landscapes. Just about all landscape plants in the rose family will require it, including roses themselves and all fruit trees such as peach, plum, nectarine, pluots, apricots, apples, pears, etc.
Usually pomegranate and fig will not, but I have seen pomegranate with yellowing and needing iron. Seldom do pine trees need it or most evergreens (those that keep their leaves or needles through the winter).
As far as landscape trees go, most (such as ash, mulberry and olive) will not need an iron application. But a safe bet is, if it is in the rose family, it will probably need one.
Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at firstname.lastname@example.org. Visit his blog at xtremehorticulture.blogspot.com.