This video js about what can happen to bamboo divisions in the first year

This division of Borinda papyrifera was made late last year, a lot of top growth was removed and it was planted in the front garden
It stated to put up some nice culms, most of which got to a few inches in height, then stopped growing

It’s nothing to worry about, the recently divided rhizome can’t support his growth, but then makes smaller culms which grow ok

Same with Borinda KR4175, which was a division that was made earlier this year