When you started your ground layering of this tree did you read up on it first?
To ground layer a tree branch you need a few items
1). good growing, long, easily bent branch
2). two "pins" to hold the branch in the shallow trench
3). watering can to keep the soil moist
enough to promote root growth
Once you have bent the branch down and determined where you will be able to get good ground contact you then dig a shallow trench for the branch to lay in.
Now score the branch in the contact area (rooting hormone is considered optional in this method), removing any leaves that would be buried helps the branch form
roots at the point of contact.
With this done you need two pins, these can be made of metal or branch
wood from any pruning (my preference).
These are pushed into the ground so they hold the branch tight to the soil, one on each side of the contact point, then you mound the soil from the trench over the branch and
water gently so the soil isn't displaced.
Now you monitor the soil, keeping it moist (not soaking wet), it will take two to four months for roots to form (at which point the branch tip
should start growing again).
After you notice the tip growing again, carefully pull back the soil mound to check the root formation, if there are lots of them, cut the branch loose and plant the new tree.
If you don't feel like there are enough roots yet, just put the soil back over the branch, water gently and continue waiting.
I like to dissolve some B-Complex vitamins and water with that solution all the time I am rooting a branch this way. I also use this solution when I water in any new planting.
This method is almost as effective as air layering and for stubborn rooters it is one of the best if not only ways to get a well rooted cutting.
Branches that this is done to can also be used like living guy wires (they will offer some support to the parent tree but they are not the best solution for propping up a leaning tree).