Leaves on F&E Hydrangea turning yellow
I have two F&E hydrangeas that were planted three years ago. The plants have always been healthy, but very slow growing and did not bloom after the first year. They are planted in an area that gets almost full sun. The soil is pretty heavy, but I amended it when I planted them.
This past week, I have noticed that the leaves are yellow with green veins. From doing a little research I see that this can be due to an iron deficiency. I also saw that heavy soils or sometimes too alkaline soil can cause this. I have not had my soil tested. I do have some azaleas in another bed that are suffering from the same thing. I have many other hydrangeas in the same bed as the hydrangeas with the leaf issue that do not have the yellowing, but it is a very large bed. Almost all the hydrangeas (about 20) in this bed are slow growing actually.
With the information provided, do you think it could be an iron deficiency or that I could do any harm in treating it as such if I'm not 100% sure? I am seriously considering digging up the poorest growers and reamending the soil to see if that helps with their growth. (Sorry, I am going on a tangent and talking about two different issues now)