Something has gone wring with my jade tree. It has two trunks, connected at the root, a large main trunk and a smaller secondary trunk. The jade mostly stays outdoors in almost full sun; I bring it inside when we have a lot of rain, because it tends to get corky otherwise.

About 3-4 weeks ago it dropped several leaves. New branches are growing in where those leaves were, so I didn't worry. But then last week, the main trunk suddenly fell over. The base of the trunk looked as though it had grown narrow, so the plant had become top-heavy and fallen over. Tonight, though, I learned that it's something else: the base had become sort of hollow and tonight the bark tore and the entire trunk came off in my hand.

The trunk is not dried up or dead-looking in any way, and in fact it leaked some fluid when it broke off. It looks great above the tear.

I am pretty shocked. The trunk has grown a lot recently, and I am wondering if that could have caused this problem. I know jades are legendary for sucking up more water than they can handle- would that have caused this weak, hollow stem? Or is something else wrong? The other trunk looks fine.

Right now my plan is to trim and root the broken trunk. I have trimmed off all the hollowness- a small amount of it extended up into the plant. If you have any ideas what could have caused this, please do share them.