Q.My Rowan Has A Single Stem 4’6” Tall And Masses Of Short Side Shoots And Leaves.
I don’t know the name of my Rowan. I thought it was an Olympic Flame (labelled as such) but so far it hasn’t flowered so it’s hard to tell. Leaf looks similar but they didn’t start out purple. – they were green from the start. but info I’ve read recently says Olympic Flame have few side shoots. Mine is nothing but side shoots! It was new 18 months ago. And didn’t grow at all last year but this year it’s turned into a perpendicular mass of leaves. From the base to tip. Maybe they will turn into branches? I have a small garden in Gloucestershire in the SW of England. I could send an image. What to do? Can’t seem to upload photo on my ancient iPad.

Certified GKH Gardening Expert
It is supposed to be a small, columnar tree, but I see what you mean about no branches.
I would remove about 1/3 of the tree's branches from the bottom going up, and see if that helps. Here is more information"
https://www.rhs.org.uk/Plants/354868/Sorbus-ulleungensis-Olympic-Flame/Details