Question
I'm hoping to locate software that will enable me to plug in numbers for ultimate plant size and move items thus represented from spot to spot on a two dimensional diagram of my yard and (possible), bed shapes and sizes. Seems like an obvious way to avoid lots of math and the labor of moving mistakes. Anything out there that's more than pretty pictures requiring more effort to use than the result justifies?

Answer
Joan,
It's best to shop around,that's for certain. I bought one off of Ebay once and it was not compatible with my version of Windows,which the seller said that it was. I got a refund though.
Wherever you buy iy make sure you keep your receipt in case it isn't what you wanted and then you can retutn it.
It is very frustrating to buy expensive software and you can't use it.

I don't do a whole lot of design work now but when I do I usually draw mine out from photos but to be more accurate and to see exactly what and how many plants you will need it is best to do it right the first time.Putting in all your variables of the lot and house and existing structures is the best way to achieve a look that you have in your mind. Get a software program that also has a library of plants on it.
I would go to Google and run a direct search by typing in Gardening software or Landscaping software.
Google is a great search engine and I use it for everything.You will get MANY results and shop away.
Good luck on your gardening endeavors!