Leaf Drop on Clown Begonia
About 8 weeks ago I purchased a Clown Begonia (begonia maculata wightii) via the internet. It has put out 5 or 6 new leaves since then. However the leaves get to be from 2 to 5" long and then fall off the plant. The leaf separates at the stem end of the leaf petiole and it is a clean break with no sign of disease of any kind. In contrast I purchased a begonia Sofie Cecile and a begonia Pink Parade at the same time. These are potted in the same soil mixture (8 parts rich loam, 2 parts coarse sand and 3 parts medium perlite)and have the same light exposure. They are doing extremely well with no problems. The Sofie Cecile is doing especially well. It hasn't produced as many new leaves as the Clown begonia but they are very robust! Any suggestions would be much appreciated. Thanks.