We used to call that long 'grass' stuff 'lallang' It would shred your clothing in a short while. As I recall, it had little barbs running down the edges so even when it was cut short it would start to chomp away at your thin rubberised lightweight jungle boots. So high protected 'boots combat' became the norm. I never remember it that long though as I think it was cropped and used for whatever they used it for in Malaya and SVn