Hi there! Unfortunately, you need to cut until you see "white wood" as they call it - no black or brown. You need to be sure to sterilize your shears with rubbing alcohol in between cuts, otherwise it will spread more. Do this as soon as you can, it spreads quickly. The tree will 100% die if you don't cut. you have nothing to lose.

You need to figure out why it's rotting in the first place, which is typically due to cold / and or excessive wet. If the soil is not draining well and it's staying wet too long or it gets below about 45 degrees it can cause rot. If it's been fine for 10 years, what has changed in this plant's environment? Get cutting & then let's figure out what's causing it. Please let us know what happens. Best of luck, Emily

Thanks for the reply! unfortunately it happened while I was away at college, so I didn't catch it until pretty late. If end up having to cut it down to just the trunk will it definitely die? the trunk and lowest limbs feel pretty hard but pretty much all the upper part of the plant is squishy and the wood is dark brown. is it worth it? Does the plant really have a chance if it has no leaves left? thanks

It is certainly worth a shot - it can survive with only a trunk, it will seal off & grow new branches or leaves if it can make it. People even root "center cuts" sometimes, as in no tips, just a slice mid branch, so it can be done. You have the trunk and roots and that's what's important. I think you have a better chance than with one trying to root.

What is the season where you are? They try to go dormant in the winter so even indoors will have slower growth due to reduced daylight.

Give it a shot, don't forget to sterilize shears between cuts! Go on, scoot! Make your first cut about an inch below where it feels soft. Inspect. Brown? Sterlize and re-cut. White and clean? Then you're good. Don't let the cut get wet and just let it seal or you can seal it with caulk.