The hypothetical high plateau on Earth will be one of the colder and drier places on planet Earth (like the Atacama desert in peru, for example) but Hellas is one of the "warmer" and 'wetter" places on Mars*. Atmospheric processes will likely act to freeze-fry the high plateau on Earth, but to maintain ice concentrations in Hellas.

* For "warmer" read "less intensely cold"
and for "wetter" read "with more available ice"

A simple greenhouse would allow enough warmth for liquid water and the pressure is JUST sufficient to allow liquid water at ambient pressure. One could conceive of some sort of sci-fi plant that had an internal pressurised cell with liquid water, a transparent "window" and a tough outer integument, like the Stone-Plants of Earth, but better.

I suspect, though, that in order for a higher plant like that to survive, there would need to be microorganisms in the soil, unless you also incorporated various microbes into root nodules such as leguminous plants have.

Just wait a few hundred million years. Mars will get warmer. Surface life there will become easier**.

** = Less extremely difficult