Zyra's ult ignores her plants (gameplay)

This morning I played Zyra on ARAM and noticed that her ult ignores her plants. I wasn't sure if it was a bug or I'm just a bad player so I decided to play her in a normal game. Same thing happened again. Everytime I ult on top of my plants it just deals some damage, but it doesn't trigger my plants (like my q or e does + it should give some extra damage and attack speed to my plants).