In case you did not find an answer yet, there is a link below that I found regarding health conditions and proper care for your tree. "Unhappy serissa bonsai trees shed their leaves," so this technically means your tree isn't completely unhappy, if it hasn't let go of its leaves yet. Keep it out of DIRECT sunlight, and not too much water. Having it indoors by a window might also be a good idea, so that it can recover in a stabilized environment (despite it being a good outdoor tree). Hope this helps. Here is a link that might be useful: Serissa Bonsai Trees

aking, I believe you can kiss your bonsai goodbye. Caring for bonsai is most tedious and unless you are experienced in the care of bonsai, you always run into heaps of problems. Watering is the crux of the problem, either overwatering (causing root rot) or underwatering (roots dry out and is a road of no return) are 2 major problems. I believe in your case the roots dried up due to the over-exposure to strong sunlight; 12 hours is sufficient time to kill a bonsai. If your pot has good large holes, then overwatering is unlikely as it drains well. It takes days for roots sitting in water to drown and rot due to the absence of oxygen. In root rot, the tree die from the top and the death is slow and lingering. When the roots die from totally dry soil, the tree die from the bottom up and the death rate is pretty fast. I hope you haven't paid too much for your plant. In future rig up a automatic drip from a porous tube, with a plastic tube attached to a beaker of water. As the plant takes in the water from the soil, water leaches out of the porus tube due to osmotic pull. Air pressure then forces water from the beaker into the vacant space in the tube, keeping the tube full all the time. You can control the flow of the drip by raising or lowering the height of the beaker in relation to the tube. Raising allows gravity to assist the drip while lowering makes it work against gravity, thus slowering the rate of drip. This setup is mainly labour saving and you need to fill the beaker like once in 1 to 2 weeks. I have this system working on some of my bonsai and it works beautifully. Don't give up and better luck will come your way.

Are these in the original pots that they came in or did you transplant them over to new pots? It is best to keep them in the original pots that they came in to avoid disturbing the roots. Any disturbance to the roots while they are growing, budding, blooming will affect the plants' flower bud developments and flowering. They will recover. Keep them in a cool spot, with filter partial shade is best. You can plant them in late August or early Sept.

Rachel, it's very hard for me to make an assessment when I am not physically there to examine your plant. I don't quite understand what you mean by soft but not overly. I see that your last picture you had lost a couple of stems, so perhaps if its really rot setting in the base, you need to catch where is the rot happening at. If it's right under all the stems towards the roots, you are better of cutting off as much rot/brown portion as possible until you see healthy green stems, and try to root the cutting as best as you can. At this point, you can try to snap 1 or 2 healthy cuttings at the tip end towards the base. Always let the cuttings dry up and callous before their to root them in new soil. And also make sure when you snap them apart, the stem must be close as to the root base as possible, if you can snap some roots with the stem even better.