What's growing in the container plantings? Edibles? If so, it's entirely possible that they may be attracting rodents - they are smart enough to take advantage of any free food source.

But there's a bit of a disconnect between a "container garden out back" and rodents getting into a building. Rodents - rats especially, but also mice, squirrels and raccoons - are omnipresent in urban settings whether you ever see them or not and they will invade buildings if they find a way. Buildings offer safe, dry habitat and easy access to food sources, so if they find a way in, they will invade and set up housekeeping.......it doesn't really matter what you are growing where.

Building management needs to focus its attention on discovering how these creatures are entering the structure - openings in soffets, doors that don't close tightly, cracks, window screens with holes, branches that touch roofs or balconies, etc. - and make corrections and repairs to prevent entry. Once that is accomplished, it doesn't really matter what is being grown in what proximity - the rodents will be prevented from entering.

Just a question, but any thick groundcover plantings close by? Like ivy? Dense layers of groundcovers are also a very attractive habitat for rodents and if something like that is present close by, that would explain the increased presence of rodents. Any neighbors with pets that might leave food out on balconies? Pet food is a guaranteed attractant for rodents........far more appealing than anything grown in a container.