They like wet feet,but can be over watered.Let it dry out a bit and stop fertilizing and pruning.Check the soil every day if its moist don't water. Try to keep it moist,but not saturatrd.It needs direct sun every day.In my experince when they have faded as far as yours its hard to bring back,but don't give up.

Thanks. I will try that. I have already put it on my windowsill and the soil has already started to dry out a bit, though it's still moist when I touch it. I hope I can save it. I will get back to you all in about a week and tell you how it's doing. If there is any more advice out there, I (and my serissa) will be very grateful!

Woody,
This regimen has worked for me over the years with my serissa. I fertilize with Miracle Grow every two weeks during the summer. One table spoon per gallon of water. On occasion I will feed a dose of Super Thrive. When the out side temp drops below 55F.,I bring it inside and keep it under a grow lamp 10 to 12 hours a day all winter,fertilizing once a month. Repot every two years in early spring,but don't prune roots too heavely. Prune leaf buds during summer to promote blooms. It is normal to see a few yellowing leaves on a healthy plant from time to time. Hope this works for you. Don.

The bonsai fertilizer I have got is called Tokonoma bonsai food. On the bottle it says there is 4% nitrogen, 6% phosphorus pentoxide, and 6% potassium oxide. Would I be better off getting some miracle grow then or will that be okay? I used to have reptiles and I am sure I have still got a UV light somewhere in the house. Should I try and find it to use for my tree? We get hardly any sun here, it has been dull & grey for about 4 weeks now, so even on the windowsill it isn't getting any sunlight.

I have just been taking the last of the brown/black leaves off, now there is only about 12 leaves left on the whole tree, but I can see a tiny little fresh bud (really tiny), there is only one though. Hopefully it will grow some more buds. I am going to look for that light in a bit, so I should be able to put it over the tree today. The soil is drying out a bit more, I have just felt in the hole underneath and it's still just a tiny bit moist. Do I need to water or fertilize before I put the light over it? I read on another post on this website that you should use a humidity tray. Is this so for the serissa?

I think you will see better results with Miracle Grow. It has way more Nitrogen and will keep those leaves green. I have tried many fertilizers,but see better results with Miracle on my Serissa. If you are seeing new growth then its making a come back. I have never used a humidity tray, but live in South Central U.S. where humidity is not a problem. I could not get mine through winter without a grow light. If its not getting any direct sun,use the light. Keep it watered and let it come back before you fertilize again. Looks like you are on the right track.Good luck.