My brother is preparing to fertilize the pecan trees. I have one right in the middle of my garden. Although I want the tree to live and produce, I'm concerned about the grass and my flowers and the fertilizing plan. The tree in question has a trunk size of at least 10-12 inches and the tree canopy is at least 15-20 foot. It's probably 15 years old and is pretty healthy. I don't have anything planted near the trunk but there probably will be something planted under the canopy one day. And there lots of stuff already planted just outside it's canopy. Here's some snippets of the info he got from the extension service. NITROGEN (ammonium sulfate) For mature trees: Apply Nitrogen of 21-0-0 or 33-0-0 for each trunk diameter. Apply on the surface starting 3 to 5 feet from the trunk and extend out a few feet past the tree canopy. The nitrogen doesn't concern me as much as the following: ZINC Frequent zinc sprays for the foliage are essential for rapid tree growth. Recommended: Zinc nitrate and Zinc Sulfate. Can cause leaf burn on other trees especially peaches and other stone fruits. Has minimal hazard to man and animals. I told him NOT to do anything to that tree until I found out more about his plan. I know absolutely nothing about this and could really use some input. Thanks in advance for your help!