Having worked pretty hard manual labor doing 12+ hour days 6 days a week, I promise you we are all looking at our watches starting at about Thursday. The people who didn’t have a clock near them were horribly annoying asking what time it was every fifteen minutes. Those kind of hours doing manual labor tear your body down. I saw the lifers in that line of work, and decided it was best to keep my back and knees functional.
With that being said, landscaping is a wonderful career and it’s a good way to stay fit. I just strongly advise not working 60 plus hours a week, but I recommend that for any job, outside or in an office. You dont have to avoid working outside, just do what you can to limit extreme hours and do a lot of mobility excersises such as yoga or a dedicated stretching time.