There is Spanish moss draping the trees all over Northern Florida and much of the humid American Southeast. Actually, Spanish moss isn't a moss at all, but a Bromeliad - an air plant - and makes a lovely, soft, grayish green, soil cover for container gardens.
If you collect it yourself, first make sure there aren't any frogs or other creatures hiding in it. When you get it home, you can keep it alive by keeping it moist, or dry it, which is a good idea if you want to bring it indoors, because it can harbor insects.
To dry Spanish moss, put it in the microwave for one to three minutes, depending on how powerful your oven is. You can then tuck the moss in around the plants in your container gardens. It can give a nice finished look, or if your container is a little sparse, you can use the Spanish moss to fill in some of the extra space. It can also be used to hide an unfinished pot rim.
You can also buy Spanish moss.