They're just starting to ripen on the trees in central Texas this time of year. I haven't had black sapote yet so I can't compare the taste. Being in the area for the first time, I've only had a few so far. They tend to have a mild, floral persimmon flavor combined with blackberry but without the acidity. Not bad at all for a wild fruit, though I can see that the seed-to-flesh ratio is why it's recommended to strain them in bulk to make jellies and jams. Fruits do ripen fine off the tree if picked when green but only if at mature size.
I went out and bought a 3ft. female tree from a local nursery that specializes in native plants. Pollination shouldn't be an issue with male trees in the region. In hard clay, alkaline ground with no amendments since this past June and it has done well in the scorching 100+ F dry summer in full sun. Even sent out a couple new taproots.
Sent you a PM about seeds.
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Fruit + seeds (water bottle for scale)
Young tree (3ft.)