From what I got of it, she fell off the swing and went into early labor. She then ended up dying during child birth because of this. Is that what y'all got from it, or have I completely missed it?
You have it right for the movie version. In the book she falls out of a tree. Also just as a note in the book the parents die of cholera not an earthquake.
I really thought there was a different explanation in the movie for why/how she died.
Of course I don't understand why the father abandoned Colin. He seemed to be a nice, caring person. It does not make sense he would abandon a child because his mother fell off a swing.
If the garden was closed because the man's wife fell of a swing, it seems stupid to leave the swing and close off the garden.
I try to analyze very many movies, I don't think I am going to try with this one.
However she died, I understood the movie as that the garden was the place that she loved as well as the place that she died. He couldn't stand to be in the garden without thinking of her dying there. If he didn't go into the garden, he wouldn't have to think of his great love lost. At least that's how I take it. It's along the lines of "if I don't see it, it didn't happen." In other words, I believe it to be his way of grieving for his deceased wife.