My experience from commercial property landscaping is that my lifts actually went down for the first couple of months. But then they started to steadily creep back up. That was in Huntsville. 2 days after the people running the gig pulled out, I went to work at a carwash in a town that's technically part of Houston.
That was even harder than the landscaping. It's a little hotter and way more humid in Houston so I had to readjust to the heat all over again. God I hated doing rims. No shade, knees, back, and ankles aching, the concrete both reflected and radiated heat back at me with my face just a couple feet from the ground.
But you know what, I was still able to gain muscle and strength. Over something between several and many months, I was able to do a 4 day Westside BB style split over a 10 day week using the volume per day I could before the landscaping.
Even now while I work on my teacher's certificate to teach high school science, I work in a produce department lifting and carrying 20-60lb boxes and sacks of produce and pushing and dragging heavy carts around. Of course, since I'm bigger and stronger looking than most people I do most of the heavy grunt work while directing my coworkers when the department manager's not there... but tbh I kind of like it that way haha.
What I found is that the longer I did those kinds of jobs, the less they would take away from the lifting.
With the landscaping and produce job, my joints actually feel a lot better than they do with desk jobs. I really think it's all the walking, carrying, and pushing that helps. At the car wash, my joints always hurt a little because of the constant bending from vacuuming and the kneeling from doing rims.
Ideal? No. But certainly not a show stopper. We make do with the card dealt to us. Such is life.
Best of luck in all your endeavors!