I'm using mulch on my trees and shrubs here in upper SC. We have heavy clay soils. I've been putting mulch around all the trees and shrubs I plant, but I feel like some of them don't need it anymore or at least there is a point when the benefit doesn't out weigh any expense or effort.
For instance, we planted a maple tree in the yard. There aren't any flowers or berries that need the extra moisture retention and I'm sure after the 3-4 years it's been since I planted it, the roots have grown deeper and wider than the one bag of mulch I put on it can cover. I feel like I'm wasting my time and effort. Like it's only there to prevent someone from hitting the trunk with the mower. The same thing goes with my crepe myrtles. I feel like they're starting to get big enough that my bag of fertilizer isn't doing what it once was.
Other of my plants, I'll probably continue mulching because I feel it helps with flowering or fruiting. For instance, my azaleas, small magnolias, flowering cherry, figs, blueberries, etc... However, I just planted some pecan trees and I feel like once they get big enough, it's no longer helping enough to justify buying it and putting it out.
Occasionally, they have a good deal around here with Homedepot putting it on sale at 5 bags for $10, so it's not that expensive, but at current count, I'm taking care of 28 trees, shrubs, etc... It'll add up. Not to mention me having to lug them around and put them out.
So what do you guys think? Is there a certain point where it's no longer helpful to mulch? Like if they get over a certain size or if they've been planted a couple of years and you're not trying to get fruit off of them. Thanks for the help. I'm in Zone 8A.