What zone will this fruit grow in, and when is it in season?
These seem to only do very well in tropical climates and also at high elevations, however, they will grow elsewhere. Just not as productively. As for when they are in season, it can be hard to say. They will fruit, and ripen at different times during its growing season.
This article will give you some more information: https://www.gardeningknowhow.com/edible/fruits/soursop/soursop-tree-care.htm
I bought a cherimoya tree about 3 ft tall, not sure if it's grafted or from seed. I noticed there is a crack (but it already closed) at the bottom of the stem, it was originally covered by the dirt so it was not very obvious. Can this tree survive? The crack looks pretty deep but the tree appears to close the wound. Is there something I can do to help it survive like wrapping a tape around the stem or something like that? Please help.
At this point, the wound has already healed over. This should not cause much concern for the tree in the future. Just care for it, as usual, and it will do just fine!
This article will help you to care for the tree:
Since October 2020 the Cherimoya tree dropped the leaves . It’s April and no leaves yet. What should I do now?
You can test the tree for life by using the "Scratch Test". This article will help:
If the tree is still alive, then this article will help you to know what care it needs to survive, happily: