Almost like a cross between a cleft and bark graft like this?
Yes, pretty much like that.
Cool. Thanks! Did he mention anything about fertilizers for in-ground mamey trees?
No, I don't believe so. He did show a couple of videos that are available on line that he and his father (Pablo Lara) did, one in English and the other in Spanish. They focused mainly on mango cultivars. They intend to do more in the future.
He discussed a few of the mamey cultivars: 'Pantin' - gets soft/slimy after a few days in the refrigerator. Best mamey rootstock as it produces a thicker stem on the seedling. 'Magana' has ripening issues, where sometimes it will ripen on one side of the fruit and not the other. He suggested that many people scratch the skin on the end when they should scratch it at the middle for 'Magana', and on multiple sides. 'Pace' is a hybrid between Tazumal (sp?) and 'Magana' that was developed by his father. The name is derived from the first two letters of his father's name, and the first two letters of his mother's name (Cecilia?). It ripens at the same time as 'Magana', but ripens evenly, and is precocious. He mentioned 3 cultivars from the Yucatan Peninsula (spelling may be off): 'Cepeda Especial', 'Akil Especial', and 'Vidal Redondo'. All were said to have a very good flavor and a reddish flesh. He may be selling those at Lara Farms (Homestead).
Since he had no ripe mameys, he brought in some ripe caimitos. He had two types (seedlings), one with purple flesh and the other with half purple/half white flesh.
A few of other tidbits that he shared (general, for all fruit trees) that are probably familiar to most of us:
"Fruit trees will not drink old water." Translation: Use a well drained soil and let them dry out before re-watering.
"Don't use black soil or potting soil in the planting hole." To clarity, you should leave the potting soil that was attached to the roots from the pot, just don't add any additional.
(Specifically for mamey) - Prune larger trees to let more light in, or else you will only get fruit on the tips of the trees.
"Leave circling roots when planting potted plants." This was a new one on me, but I'm assuming that he believes that it is more important to NOT disturb the roots.
On a side note, Chris Rollins shared one of the first fruits of
Psidium acutangulum (or a very similar sounding species) at the Fruit & Spice Park. Flavor was similar to Cas guava. Nice.