I have three Magnolias. Two in very large tubs and one in the soil. Between four and seven feet high with very healthy looking foliage. They are all five years old at least and none have ever flowered. Please can you tell me if I am being impatient or doing something wrong?
Most magnolia species take years to bloom, on average about 10 years, so their young age is the most likely reason your trees are not flowering. If you know the varieties, you can look up the age at which they're expected to bloom.
Here are a few other possibilties: