Bald Cypress Development
From Sapling
when it had roots that went straight down the pot walls. I got basal flare by cutting off the bottom and repotting into shallower pots every couple of years.
I got good taper by cutting it back and wiring up a new leader.
It is now fairly well tapered and about 30" tall with a 3" trunk above the flare—after 10 years.
Now use wooden boxes with mesh bottoms for getting trees to develop fast vs. pots.
I would let the new leader grow for 2 seasons before cutting back to a new leader
You can probably wire a new leader up now along the current trunk and then make the chop in the spring if you decide to take that approach.
The new leader should grow a bit stronger in an upright mode.
I also made my chops at an angle to the back and they all worked on the bald cypress, but have not worked on some other species.
I now chop square an inch or so above the new leader and cut back once the sap has withdrawn.
I would not due the chop and the repot into the box in the same year. I would suggest replanting this coming spring.
Where to chop depends upon how much taper you want to develop.
To develop lots of taper, chop low (1/4-1/3 of final height), allow to grow a couple of seasons, repeat by chopping the new growth at 1/4-1/3 of the remaining final height (as if the previous chop was ground level), and repeat a few times.
I chopped mine at 1/2 and 85% of final height and have some nice taper, but not extreme.
Waiting a season normally means an entire growing year. However, if they are growing like weeds then you may be able to get away with two operations. I am more willing to push when dealing with lower cost material like end of season nursery stock if it grows wild since it is not a huge loss if I set it back or even kill it.