I planted a bunch of thuja green giants in my backyard last year. I am wondering the process for fertilizing them every year. What type? In ground or above ground? How much? How often? Thank you.
I’d suggest feeding them now as they come out of dormancy. Arborvitae are an exception among evergreens in that they don’t like acid soil so most evergreen foods like Holly-Tone with added sulfur are NOT appropriate for arbs. I use Tree-Tone which has all they need but no sulfur. Take a small pipe (I use and old tire iron) and poke 5-7 holes around each plant into the soil out away from the trunks about as far as the outermost branch tips. Make the holes about a foot deep and an inch or two wide. Fill the holes almost to the top with the Tree-Tone and that’s it! One feeding now when the season is just starting is all that is needed. After a few years when they are well-established, feeding isn’t really necessary.