Bit of a story about my Sophora microphylla...
I bought it as a stick in a pot some 10 years ago.
I've always had the "problem" with it contorting. It grows zig zag into itself, forming a dense round bush. Cut it back and it just does again.....year after year after year.
When it was about 40mm thick I air layered it just above ground level....and took the top off. I wanted to shorten the trunk some.
I removed the layered top and planted it in a flat container.
After some time (can't remember how long) the bottom stump (I just left the big pot with stump to throw away later...never did) sent out a side shoot. It grew rapidly as the roots escaped into the ground.
It grew straight up to about 2.5m...and never contorted again.
I planted it in my garden a few weeks ago.
Here it is...with a Southern Rata in the background.
Here's the air layered top. Its about 3 years old now...still contorting.
There's some nice character inside that bush....but it can't be seen as it covers itself continuously.
TBH I don't really know what to do with it. It naturally contorts until it reaches a certain height...then it grows normal. Keep it small and it contorts.
Apparently its a habit they evolved to protect themselves from the now extinct Moa that fed on their leaves....according to scientists.