Most magnolias have very large, glossy leaves that are alternate. You can easily tell whether your magnolia tree feels good all around by the color of the leaves.
Yellowing of the magnolia leaves indicates a nutrient deficiency
Not all magnolias are deciduous
Many magnolia species shed their leaves in the fall, but there are also evergreen varieties. The difference is due to the different origins of the trees, because some magnolias come from regions that are always warm. The rule of thumb is that evergreen magnolia varieties are usually only slightly or not at all hardy and should therefore be cultivated either in pots or planted out in mild regions (e.g. the German wine-growing regions). The deciduous magnolias first flower and then develop their leaves. Leaves and flowers can only appear at the same time for a possible second flowering in summer.
Leaves turn brown
Brown leaves on magnolias usually indicate either damage from late frosts and/or an unsuitable location - the magnolia simply does not feel well and shows this with the color of the leaves. Magnolias need a sunny (but not too sunny) and wind-protected location, and the soil should be as loose as possible, rich in humus and slightly acidic. Brown spots, on the other hand, are a sign of leaf spot disease, which is caused by a fungus. It occurs mainly in warm but humid weather conditions.
Leaves turn yellow
Yellow colored leaves always indicate a nutrient deficiency. This can happen because the roots are either unable to absorb nutrients and transport them to the upper leaf areas due to heavy soil or waterlogging (caution, risk of rotting!) or because there are simply not enough nutrients in the soil. For optimal nutrient uptake, magnolias need slightly acidic to acidic soil with a pH between 5.5 and 6.8. In many cases, the yellow leaves of the magnolia indicate a lack of magnesium or iron. Fertilizing with a rhododendron fertilizer is not wrong in such a case.
tips
Magnolias need quite a lot of water and should therefore be watered in dry seasons and hot periods. However, you should be careful not to pour the irrigation water over the leaves and flowers.