Magnesium immissions consist of 65-80% of MgO. They increase soil alcali reaction up to pH 9.2 and unfavourably turn soil structure from the crumb structure into the prismatic one. On the affected sites, about 10 plant species predominate among which Ph. australis begun to spread, as a new ecotype, during last 20 years. Ph. australis forms mostly elliptic-circular patches of 20-33 m in diameter on the place of former pastures and forests where it did not occur before construction of the magnesium plant. In average, 21 stems (1 fertile) per m2 grew up in one year in the close vicinity of the immission source, while 44 (6 fertile) in the distance of 1800 m. Number of internodia did not exceed 22. After Agrostis stolonifera, Phragmites australis shows the highest vitality in such habitats. It grows even on alkaline soils with pH 9.1 and level of Mg and Ca of 13.528 mg.kg-1 and 1163 mg.kg-1 respectively. Ph. australis is a perspective dominants, resistant and technically usable species exhibiting an antierosive effect and allowing an alternative solution of soil reclamation and vegetation regeneration in surroundings of magnesium plants.