But how would the stalk grow if it just gets burnt off once it breaks the surface?
Well the roots would lie dormant in the ground, waiting for the local burncumference to die off (through soil depletion). Then the sproutstalks would grow back and have a little time in the sun before the burncumference populations return. That new generation of glass flora would "kill" the new gen of black flora, re-fertilizing the soil for themselves and repeating the process.