Without liquid water in the upper few meters of the ground, the result is pretty predictable. I think there was some evidence of water at or close to the surface, but if I remember correctly only in salty solutions where the salts prevent the water from freezing at Mars temperatures. Maybe you could find some plant that can make use of that water but then the plant would still have to be able to control its temperature so that it does not freeze solid. I would not definitely rule it out, for that I know not enough about plants and Mars, but to me it seems at best barely possible. Which of course is still possible.
