dyonoi:

the main thing is that theres a hive next to them with green awnings that doesnt match either olive, limeblood or jade colored trolls and that look really blobby compared to the triangles/rectangles of the other visible hives

when you color correct the color on karkats hive in the same snap to his original color at the same rate as the green, you effectively end up with jades color too (i didnt make it match 100% exactly cause theres video compression to take into account but that looks p definitive to me)

but hey i went full fucking BKEW and slapped this together for you anon

(heres a bigger version)

in conclusion: im 80% sure that jade is their neighbor that hangs out with them often, and her hive has been fucking taken over by plants Habitat (1997) style