On Thu, 20 Nov 2014 wrote:

Not only are there golf carts, but there are also similar small
electric vehicles with flat beds, designed for hauling stuff around
that would be more appropriate.

Yep. That is what the gardeners use at the botanical garden. Not cheap.
This one is $10,995: http://www.ebay.com/itm/261659871415

Cheaper is a used golf cart with platform on the back:
http://www.ebay.com/itm/291303368043
But the OP doesn't have space in his garage for one.

My mom uses a garden wagon. Somewhat like this one:
http://www.ebay.com/itm/151484721694

Maybe the OP could use something to tow it. (There are many listings for
this cart on eBay.)

Don. www.donwiss.com (e-mail link at home page bottom).