As a general rule, never mulch more than 3 inches deep most mulching requirements are from 1-3 inches. For annuals, groundcovers and most perennials, 1-2 inches is sufficient. For larger trees and shrubs and general landscape beds, 2-3 inches will be fine. Before adding new mulch to existing beds, it is suggested that you 'fluff' up the existing mulch, and then evaluate whether or not additional mulch is needed. This process, over time, can cause eventual decay of the bark, and possibly death to the tree.
Container gardening is very mobile.
It can be quick, and is a great way for a quick fix, quick screen, quick spruce-up, and can be long or short term. And, it offers easier gardening opportunities to the 'seniors', physically disabled, the kids, and just about anyone who wants to do a little gardening. You'll love it, and you're plants will love it. If you're a first-time gardener, growing plants in containers is an easy, and safe way to get started. It's great for the newcomers, but the experienced folks will tell you how much fun gardening can be when you're doing it in pots.