HelpfulGardener.com

Hi,

I have a really large Mature Oak in my front yard (I don't know what kind of oak, Black or Scarlet maybe). I wanted to give it a good fertilizing this year as I haven't fertilized it specifically for many years. It is healthy, as far as I can tell. But last year I had to remove two medium-sized branches that were dead.

Now I don't know if the dead branches are an indication of anything, but I want to make sure. I have seen online that I should put pure nitrogen in pockets under the tree, but is that the best method? There is hardly any grass under the tree, due to lack of sunlight I assume, so grass loss isn't much of an issue.

I live in South-Eastern New Mexico, Texas border. I attached a couple of images to maybe help someone identify it, no leaves though, sorry.

Thanks!

not sure what oak it is, but I do remember when the university research farm was rehabilitating some woodlands they owned, they used ammonium nitrate crystals for the nitrogen. I don't know where they got them from, or if they are still even available.
This was for a oak/hickory association type forest in the midwest, so it maybe different in your area.
If it was me, I'd probably use a 15-15-15 fertilizer and try to mulch it with an inch or so of leaves or wood chips to keep the fertilizer in place until it breaks down.
Another possibility could be to use Ammonium Sulfate if your soil is alkaline to the point of harming the tree.
A soil test will probably give you the best info to help the tree and the State extension service should have some valuable info for free.