Just thought I'd share this as inspiration for anyone who is thinking about planting avocado seedlings for their own sake rather than strictly as rootstocks. This is
entirely anecdotal, and you can easily find anecdotal examples of avocado trees that don't flower for 20+ years, so YMMV.
But, with those caveats, we have first blooms on a seedling tree in the PNW avocado breeding project! This tree was acquired from Oliver Moore in Gainesville, FL, and was the rootstock of a grafted "Jade" tree. This is what it looked like in summer 2021 after I had mailed it to myself from FL and potted it up:
Oliver said at the time that he believed the seed for the rootstock was from the 2020 season but could have been from 2019 (I would have guessed 2019 but maybe things grow faster there than here!). He wasn't sure of the parent variety but said most of their seeds in those seasons were either May or Del Rio, and that the two trees were also in close proximity and likely pollinating each other, so statistically it was likely one of those, maybe a cross of them.
You can see that the rootstock had no shoot at that time. However, in spring 2022, I decided to let this shoot grow:
Later that summer, I planted it in the ground in my greenhouse. The main trunk, grafted with Jade, is about 9 feet tall now, and covered in dense flowers just now starting to open. The rootstock branch is only about 3 or 4 feet, though I topped it around 2 feet to make it the bushy lower part of the tree. Here's the base of the tree this week (from the opposite direction, so the green trunk on the left is the pink one from 2022):
The sad looking leaves are from the last flush of the 2022 season and getting ready to drop. When I was poking around in the branches a couple days ago, lo and behold, I see two small flower panicles on one of the rootstock branches!
I doubt it'll hold fruit, but who knows! Does anyone else have stories of other precocious avocado seedlings to share?