Steven Bornfeld wrote:

My next door neighbor is an avid gardener; recently retired,
has already volunteered to help me. But I know he'd refuse payment and
I feel funny about letting him work on the yard for free--plus he's no
youngster himself and smokes heavily.

But no harm in accepting his experienced advice.

I'd just as soon get the aches and pains myself.

Contact your local High School, there are typically teens looking for
summer jobs, and even if all you have to offer is a few days yard work
word of mouth spreads.