Plant on large Asteroid?
It might depend on what qualifies as a plant.   A thin film of rugged mold for example . . . just maybe.

The tricky part is that asteroids are too small to retain an atmosphere and you need an atmosphere to have liquid water which plants and all life (so far as we know) needs.   I don't want to dismiss the possibility that there's underground water and some kind of very sturdy life that can eek out a living on the airless surface of an asteroid, but I wouldn't bet money on it.  I think it's unlikely, maybe unlikely multiplied by about 5 orders of magnitude.    It's very close to impossible.

That said, Ceres is an asteroid and Ceres may have a liquid underwater ocean.   Life in an underwater ocean is thought to be possible.