Hello again - thanks for the lovely replies!
@daydreamer and wallycat: I might try giving them a litter box, but it would indeed be problematic if other cats come and use it. Still worth a try, though. Might distract that kitten from the pot plant (or my fence...)
@Mitts&Tess: I'm so sorry, but I don't live in the US!
I don't remember what I filled in during the registration; I was disguising my identity. Here, feral cats are running rampant everywhere, and spaying/neutering is not enforced. My neighborhood has approximately 18 cats already, and I know that some of the kittens have been hit by a car, or vanished during these last few months.
I googled and found an animal shelter, but it's an on-off program, and charges for spaying/neutering.
Oh, and btw - is there any way to alleviate the poor kitten's diarrhea?
EDIT EDIT: Ok, I was typing a reply before I saw cat face's response, sorry!
@cat face: Ah, ok, that makes sense. I had been told that she is indeed marking her territory, so I guess I need to stop feeding her now.
What I don't get is that she buried her poop when she's doing it right in front of my house, but I guess she didn't really register that area as mine. Thank you so much for the detailed explanation!