I am in a low chill and hot summer area. I am in orange county, ca and get about 300- 400 chill hours. I think, but am not sure, that I have a healthy galla apple that is covered in flowers every spring but produces only a few apples a year. I have had this apple for five years.

Would a sundowner apple pollenate the galla?

Would the galla pollenate the sundowner?

The only other apples in my neighborhood are Anna and golden dorsette, but they flower too early.

There is a huge granny smith behind my house but it is sick and looks like it is dying. When it was healthy my unknown (probably galla) apple was covered in apples and had to be thinned. Should I get granny smith instead of a sundowner?