Major problem for me!!!

One would think that getting a shepherd's hook into the ground wouldn't be a big deal. Well, not so here on my little bit of ground. I pounded this thing with a huge sledge hammer until I got most of it in the ground and broke off the top of it. It still isn't all the way in. I am doing everything I know to do to soften up the clay. I have researched it on the internet, but anything more than a few (4 maybe) inches isn't going anywhere. I'm open for suggestions!