Several of the leaves on all three of my Asclepias curassavica plants are turning yellow, getting black marks, then turning brown and eventually falling off. Has any one had this problem? Or know what might be causing it? I recently had 3 generations of Monarchs that have now moved on and now the Queens are coming to lay eggs and i am concerned about the leaves. I still have plenty of green leaves to support a few generations of Queens but would really like to solve this leaf problem.
Any suggestions or shared experiences would be much appreciated. I suspect it may be due to over-watering although the plants do have excellent drainage and are in good soil. Thank you.