Silverg3mes said:

"The flower Agricarnation from Botania tries to fertilize the Path block from OpenBlocks, I see the green particle effects on them."

Hmm, this is probably an OB thing eh? :P

It has to do with this, so it's on their end.
https://github.com/OpenMods/OpenBlocks/blob/a03857c3226a8bdc7b53b498d731885bf571e5fb/src/main/java/openblocks/common/block/BlockPath.java#L12

OpenMods/OpenBlocks#459