I had the same problem
so I tilled in some sand and it made it a lot less gummy

Oh and you are going to want to put in a lot of organic matter like compost/manure/topsoil

Just courious .... how deep is the clay layer and what is below it? I had several feet of red clay followed by miles of decomposed granit. 30 years of adding OM and I think I could dig through soft,fluffy loam clear to China.

Do you have earthworms? They're great little 'field hands' to spread compost/mulch material throughout the garden.

And BTW .... your Mom is blessed to have a sweet gardening daughter to help her out.

Nothing amends any soil situation better that manures, leaves, mulches, trace minerals and cover crops. Don't overlook Mycorrhizae of the Endo type. With more and more of the organic amendments you will attract more and more native worms. They will help you most of all but they must be preceded by the soil building steps. The worms increase last and help the most like the icing on the cake.

Thanks for your responses. I wish I could send some of my leaves to her! I live in NY and my 2 acres is completely surrounded by trees. I have more leaves than I know what to do with! Unfortunately, she lives in a new development where they have taken down most of the trees.
I was only in GA for a few days, but with all of the digging we did I didn't see a single worm. Also, I don't know how deep the clay goes, but we dug up some canna that she didn't like and they were pretty deep. It was all clay as far as I saw.
I'm going to foreward all of your responses to her and she can check on buying compost/organic matter. Thanks again.

What that Georgia clay needs is organic matter, lots of organic matter. I have seen a treatise from the University of Georgia Cooperative Extension Service that states that adding sand, unless you add at least 45 percent (a considerable amount of sand) by volume sand will do little to change clay while enough organic matter to make a 5 to 8 percent level will change clay significantly.

Have your Mom check with the local garden centers and see how much they charge to deliver compost in bulk. You want to add a lot of compost if you can and buying it in bulk is much cheaper than buying it in bags from Home Depot or where ever.

If she lives in a city, some cities compost the leaves they pick up in the fall and that compost is usually quite inexpensive.

The good news is that after you work enough compost into it, clay is wonderful to garden in.

Clay + sand + heat = adobe or brick.

Clay was formed in the bowels of the oceans of the world. It contains many trace minerals that are from the bottoms of those oceans.

Get it amended as suggested above and enjoy some of the best growing medium man knows how to improve.

Get it amended and you native earthworms will just appear. There is no reason to purchase worms. You build that soil. They will come.

The mineral particles that make up clay soils were eroded from certain types of rocks, just as the mineral particles that make up the larger silt and sand soil particles. That is why some places have clay soils, some places have sand soils, and others may have a mixture. Which types of rocks were present when the soils formed determine which soil type you have today.

Just expanding on billums's suggestion... My county, and not my city, handles sanitation duties. Dekalb county offers free compost for pickup. I believe other counties do too.

GA Clay = Brick. I don't see how adding sand can make it worse. I've added sand through the years, and it seems to help. Starting last year, I've added a lot of free county compost.