IF there is green there is still life. Carefully unpot the tree and look at the roots. It sounds like the roots are no longer able to take up water.
Andi

What would I look for? and what would cause that so suddenly?

hallo Andi and greeneye. I was going to post in the lemon repotting thread, but as it's a calamondin I've just repotted perhaps it's more useful here. Andi, I took your advice and repotted the calamondin very carefully. All its leaves had dropped off and I thought it had got root rot. But in fact it seemed completely sweet, just absolutely and thoroughly root-bound in the pot. Is that perhaps what's happened to greeneye's tree?

To be on the safe side, I washed it through, though because the rootball was so dense, there's still a bit of soil in it. However, it's mostly small bits of bark, and there's really no sign or smell of rotting. I washed it through gently with ordinary water and also with a weak hydrogen peroxide solution, in case anything was lurking, then let it dry off and repotted it in Westland Citrus Compost, with a layer of crocks in the bottom. There's one small leaf bursting out of a branch, and most of the branches are actually green, so I trimmed off the dead ones and have put it somewhere bright, as you suggested - and will await the consequences.

Did you unwind the roots? If you didn't you need to.

What size pot did you repot in, the same one or larger?

If the same one, then unwind the roots and trim them; if larger then just unwind (and trim only if need to, but if it's that root bound it could probably use some).

I repotted a plant once that was very root bound and just stuck it into a larger pot. The plant died. After it died and I unpotted it, I found that all of the roots were still in a ball just like I had placed them. The plant's roots were never able to escape out of the tangled root ball to get into the new soil.

After that incident, I always loosen the roots when they circle around in the pot.

I didn't actually unwind them as such. But washing them through certainly loosened a few strands. I repotted it in a pot only about an inch larger, not a much bigger pot as a friend is going to give me some larger pretty Italian terracotta ones later in the year. Should I take it out and unwind it more, do you think? The original plastic pot was about 7 1/2 inches, the new one is 9inches across.

Since some roots were loosened and you got new dirt in between the strands and you will be repotting later on in the year, I'd probably leave it for now and see how the plant is responding and how the roots look during next repotting.

But since you say that "the rootball was so dense" I'd probably spread them and trim them just a little if they need it when you get your pretty new pot. But keep a good watch on it now.

It sounds like you take really good care of your plant. Root health is a good indicater of care.

Thanks! Though it didn't look healthy on top - it had lost all its leaves and many twigs had died back. What had happened as well was that it had an absolutely horrible infestation of scale - the remaining twigs were green but very knobbly, and I'd thought they were just beginning to become woody, but when I looked closer it was totally lumpy with scale. Ghastly! I've now cleaned every twig very gently with slightly soapy water, and hope that does it some good. Lucky it's still a very small tree - I'd hate to have to do that with a big one.

Greeneye, how are you getting on?

well... nothing new has happened to mine. I know it's not rootbound... its been living happily in its pot for a while... but theres still some room in there. its still green, but no sign of new leaves yet.

check to see if the root ball is staying too wet. Roots that have drowned will give the appearance of a tree not getting enough water, dried out leaves and dying stems. If you find this is the case you will need to re pot the tree in a soil that is free draining. You can pour 3% hydrogen peroxide through the roots before potting to kill the bacteria.
Andi

My calamondin has green leaves, and they're not falling off, but it seems to not be doing much. the leaves are speckled with a dark-ish and light-ish green color. It's almost as if it's dormant. I have a grow light, i water regularly, spray the leaves for humidity, etc, but it hasn't had much growth in awhile. I was reading this thread and thinking maybe i should re-pot it. I had it outside during the summer (bringing it in at night) and it did so well. once fall came it hasn't been looking so great.