A friend gave it to us, and it was started in a clay pot. We planted it in the yard, and it gets sun. It's 15 feet tall and looks healthy. I have heard something about using Epsom salts but wonder if you could tell us what to do. Some magnolias, especially seedlings, can take years to bloom, even longer than yours, so tree maturity may be your problem.
Magnolias do flower best in sun and prefer an acidic, loose soil.
Add organic matter to enrich the soil. But do not overapply phosphorus, since there is generally a lot in our soils. The problem lies in a plant's inability to absorb it. And possibly, if your tree is old enough, Epsom salts can help, since it helps release elements in the soil for better plant absorption. A lot of gardeners use Epsom salts, also known as magnesium sulfate, around tomatoes, roses, hibiscus, ixora, amaryllis, Christmas cactus, bougainvillea and numerous other plants.