Purple leaves looking burnt and easily drooping
I have an ornamental plum tree that originally was a root sprout from a Prunus Blieriana about 25 years ago. Has pink flowers but not double like parent. This last winter has moved from Santa Maria, where it was for 1 1/2 yrs.CA to the Central Coast (Cambria, CA. It was potted up into a barrel in 2014 in Los Angeles, CA, and is still in that barrel. It suddenly absolutely flourished when leafing out and blooming in Feb.and up until last month. The photo is after blooms finished and leaves begin to darken. It is now June and for the past month has acted like it wasn't getting enough water. Leaves drooping which perked up when watered. Now the leaves have been turning brownish and looking burnt and dropping. Looking much more stressed. I am so worried as this was a baby from my mother's much treasured double pink Blieriana which is no longer alive and I want this little tree to survive here where it was originally born, with me. It seemed to be so amazingly responsive to being moved here even if not planted in the ground yet. I just watered it and it isn't responding as it did a few weeks ago. I will go out and take a photo to include here. Please help me understand what is happening and what I can do to help my tree.
I suspect your problem is related to accumulation of salts in the barrel and high soil salinity. We have not had normal rainfall during the last 5 winters and there is accumulation of salts in field soils and containers that have been subject to irrigation and no leaching of accumulated salts. You can try leaching - extended periods of watering until water runs out of the bottom of the barrel. You may want to also attempt to repot the plant in the barrel or at least scoop out the existing soil and replace with new potting soil. Then start a watering regime that adds enough water for water to run out of the bottom each time you water. If we get normal rainfall in the rainy season, expose the plant to as much pure rain water as possible.