Most magnolias - with the exception of the evergreen magnolia - shed their leaves in autumn, which have previously changed color, just like other deciduous trees. However, if the yellowing of the leaves does not occur in autumn, but in the middle of summer or even spring, then this is chlorosis.
What to do if the leaves on my magnolia are yellow?
Yellow leaves on a magnolia can indicate chlorosis, which is caused by a lack of magnesium or iron. The treatment includes loosening the soil in the root area, adding humus or compost and targeted fertilization with magnesium (€10.00 on Amazon) and/or iron.
Causes of chlorosis
Chlorosis always indicates a deficiency, usually of the two essential nutrients magnesium (Mg) and iron (Fe). Acidic, solid soils such as those preferred by magnolias are often low in magnesium - especially since this nutrient is either present in far too low doses or not at all in most commercially available fertilizers. Furthermore, soil that is too compacted can prevent the plant from absorbing nutrients.
Treat chlorosis
As a first step, you should loosen the soil in the root area. Be careful not to damage any roots of the shallow-rooted magnolia. Work as deep as possible and dig in some humus or compost. You should then fertilize the plant with magnesium (€10.00 on Amazon) and/or iron.
Tips & Tricks
If there is a severe magnesium deficiency, fertilization with a 2 to 4% Epsom s alt solution provides quick relief.
