Found: Two Children Search for Their Mother

A negro girl and her brother have a sister who is very sick, being taken care of by their grandmother. Their mother is far away working, I think in a factory. Grandmother sends them to look for her so she can come home and pay for a doctor. One incident I remember is the children eating oranges in an orange grove and burying the peels. They find their mother eventually . . . this is all I remember. On the cover the girl and boy are standing together, she is wearing pink shorts and a white blouse.

Is it Sweet Whispers, Brother Rush by Virginia Hamilton?

No that's not it. I wish I could remember more of the book! but well, I read it a long 11/12 years ago.

Journey to Jo'burg . If you look at the alternate covers, there's one with the girl wearing pink and white.

That's the book. Thank you!