Flower placing and breaking instead of not placing at all

Hello, I’m looking for help on my EnderHaul mod again. As the title implies, this time something is wrong with the flowers.

So our mod adds Rooted End Stone (name still pending), which is basically an End equivalent to Warped Nylium. And like it, it has its own flowers and plants that can only planted on it. My friend managed to make it so that our End flowers break if put on incorrect blocks, but thats not what I wanted; I was hoping for the flower to just not place at all if its not the correct block. Does anybody know how to help?