|My tuberous begonia is doing great ~2' tall, 6-7 stems and many blossoms, however, recently, most of the stems are wilting. Upon inspection, one or more sections of the stems are "all gone" and then the rest of the stem dies. One stem still looks healthy. Any suggestions?
|It's so sad when such a spectacular plant starts to fail! The stem rot is likely caused by a fungus called Pythium ultimum. You can prevent the problem by planting tubers in well-drained soil in an area that gets good air circulation. Mulch can hold excess moisture up against stems, giving the fungus the advantage. If you can take a stem tip cutting well away from the rotted tissue, you can try to root it. Otherwise, the plant is best removed and destroyed (sad to say!). If the soil is a heavy clay or has poor drainage, you can build up a raised bed area to plant in, or incorporate vermiculite, perlite and peat moss to improve the soil. Best of luck with future begonias!|