This is effectively a TFC version of the vanilla bug https://bugs.mojang.com/browse/MC-169697.

Plants in pots will produce particles which are noticeably darker and greener than those of a normal flower pot. This appears to happen for all TFC plants, even those that to my knowledge do not utilize biome coloration at all, such as the athyrium fern:

Compare this to a normal vanilla flower pot:

This could probably be fixed for potted plants that do not utilize biome coloring at all to have that potential removed. For plants that do use biome coloring, it might be possible to special-case the affected block IDs so that while the block itself uses biome coloring, the particles associated with it do not. Vanilla does this with grass blocks, which is why the dirt particles vanilla grass blocks create are not biome-colored. (See also #2372.)

While testing this, I noticed that sea ice blocks have blue particles, presumably meaning that their particles have biome coloring applies to them as well. Is this intended?