Answer: Based on your description I suspect you are overwatering it and/or the soil is not well drained enough. This plant really needs a well drained soil. If you amended the soil heavily prior to planting then it may be due to poor drainage. In addition to well drained soil, oleanders prefer warm or hot weather and need full sun to stay healthy. It is possible the soil was still a bit cool when you transplanted as well. Finally, make sure it has not settled deeper than that it was growing in the container. I hope this helps.
Q&A Library Searching Tips