If your Hydrangea is top heavy I suspect it is since it is falling over. You can grow other plants or shrubs around it or if your bare spot in your garden is next to the Hydrangea itself than you can use the bare spot to propagate new Hydrangea bushes to fill in the bare area. If you choose to do this the method is very simple. Just take a branch from the main plant, bend it over, and bury it in the ground. Before you bury the branch, cut a notch in it or scrape a little bark off the underside. Make sure at least one leaf node will be underground. Use a brick to hold the branch down and retain moisture. When the branch forms its own roots, cut it loose and pot it like a cutting until it is large enough to be transplanted next to your existing bush. You can do this with several branches to help to increase the number of plants produced, as well as allow you to have small plants to give away as gifts to any one who has been asking about it. One other thought is have you tried staking up your bush to keep it from falling over?