Q.manganese application for established trees
We have about 40 large trees that are maganise deficient. We have treated with iron with spray on the leaves as well as 24″ application ports around tree. Need to know how to safely apply maganise to aid in problem. What do you suggest? Thank you. Hiko, NV

Certified GKH Gardening Expert
There are two elements that plants need with similar names: magnesium and manganese. To add magnesium, fertilize with dolomitic limestone or with Epsom salt (magnesium sulfate). This article explains the advantages and disadvantages of Epsom salt and how to use it:
To add manganese, foliar manganese sprays may be available, as described in this article:
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/iron-chlorosis/
A better option is to change your soil's pH to better suit the trees you are growing. This will help them take in more of the nutrients that are already in the soil. Here is more information:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
You could also add rock dust to your garden. This contains many plant nutrients, often including magnesium and manganese.