A short update. This project continues slowly but the currently available varieties have disappointing. I still have some of the Stark Spires that are just starting to fruit and I'm interested how they turn out. The only two varieties that have been fruited well drop too early, Maypole Crab and Golden Sentinel. The low productivity explains why columnar trees were not adopted by commercial orchards and instead marketed to backyard growers. I haven't grafted any columnar trees in the last 2 years.
This spring I had flowers on a Stark Scarlett Spire and Emerald Spire that were planted in 2016. One set an apple last year but it dropped early. A Crimson Spire that I bench grafted in 2015 has its first apples this year. The Scarlet Sentinel planted in 2015 may still not have any apples although it has flowered. A columnar Wijcik Macintosh that I T-budded in 2015 has not flowered yet. It was topped by rabbits in 2017/2018 when we had a deep snow. It has recovered and should flower in a year or two.
I had 4 trees that were hit by fireblight in 2018, mostly from the Urban Apple series. I chopped those off below the infection in the central leader. Those all recovered and look real healthy. Even the one that was less than a foot tall made it. Hopefully they start fruiting again next year.
I have seedlings to evaluate in the backyard that were planted in 2017 and 2018. I continue to examine them and pull out ones that don't look columnar or are not healthy. Those planted in 2017 were chewed off by rabbits at the snow line (about 3" tall) that winter. They are 3-6 ft tall but none have flowered. Ones planted in 2018 are 1.5-3' tall. I didn't have enough seeds to start trees in 2019. I did have enough apples last year to collect seeds but did not start any this spring either. I'll leave those in the fridge, collect more, and try next spring if I have time and space. Most of my nursery space has been allocated to pear trees but many of those will move out this fall or next spring.
I'll continue to monitor the shot plot I planted on my parents. It should have a few more apples this year. I do not expect it to become huntable with the current varieties. I need some of my seedlings to turn out really productive like the Maypole crab but hold into October for this to be useful. If 2 or 3 seedlings turn out, I might get excited again. But seedlings are a numbers game and growing columnar apple seedlings isn't something I will put much effort into. It is likely that this will continue to be a backyard curiosity. Regular apples, pears, and chestnuts will be my main attraction for October and apples, pears, and persimmons for November, December, and into January.