Tea is an excellent fertilizer, but I am not aware of any virtues it may have regarding spots. I have also found that coffee is good for plants that like acidic soils ... they grow as if they were doped on coffee!
This isn't my garden btw, I only take care of my mom's when I can, as she is utterly lazy in that area.
I only have plants in pots of my own, essentially tropical ones, seeds I've brought back from abroad, like a Bauhinia, a baobab, a curry tree, a few citrus plants, and a few other dwarf trees (that used to be bonsais until the day I concluded that it was vicious of me to keep plants too stunted - better to let them grow, but not too tall as all my plants need to be brought inside in winter).
You have a baobab tree?!? I've been enchanted by those ever since I read The Little Prince. How tall is it?
One time a friend and I grew a redwood and planted it in his mother's front yard, but I don't know what became of the situation. I've since learned that they don't grow singly, but last I saw it was skinny as a whip and about 5 feet tall. Maybe we can eventually make language a complete impediment to understanding. -Hobbes
Redwoods are beautiful trees too!