the fire aspect enchantment doesnt do anything

Put the summary of the bug you're having here

What I expected to happen was...:
When i enchanted some flowers as a special reward in a map im making, they should have burned mobs (had fire aspect 100)

What actually happened was...:
The mobs (peaceful, aggressive, tried most of them) didnt burn. I attempted putting fire aspect on a sword, and using an anvil instead of the command blocks i had been using, nothing worked. Flint and steel was still functional, when mobs walked through fire they started burning
1enchant something with fire aspect
2hit a mob