I have found there are several old heirlooms which ripen quite late
and also have unique flavors.
Heath Cling -- according to the Monticello website it was
traditionally harvested in September and not eaten until October or
November. I had a bad brown rot problem this year so I did not want
to wait so long to eat anything, but I did enjoy the early ones. It
is a very "meaty" peach, more like an underripe mango in texture (but
not so stringy). The flavor is fairly mild but it could get more
interesting in storage -- I am looking forward to trying this one
after the traditional 1-2 months.
Salwey -- This peach has no orange in the color, it is a light yellow
which is similar to how Heath Cling looks. It is not as meaty but is
a bit stringy. I like the taste quite a bit and it is unique. So
far this one is better than Heath Cling.
Indian Free -- I second Antons comments here, it is one of my favorite
peaches of any season. It got bad brown rot this year however.
Oldmixon Free Improved -- I am not sure what the Improved means but it
is similar to Oldmixon Free. It is a very rich-flavored white peach,
similar to Silver Logan. This one is not as late as the three above,
it is only "late" according to Peaches of New York and the other three
are "very late". Elberta is listed as "mid" there. It is interesting
how Elberta was called midseason in the early 1900s and is considered
late today. Clearly the peach season has moved up over the years! I
expect the interesting flavors of these later peaches got left behind
because the breeders were all looking early early early.