Four woody species, Tamarix tentandra Pallas, Populus alba L. and Robinia pseudoacacia L. (planted) and Amorpha fruticosa L. (naturally colonized) were studied at two fly ash deposit lagoons, weathered 3 (L1) and 11 years (L2). All species were assessed in terms of their invasive ability, photosynthetic efficiency, photosynthetic pigments and damage symptoms, while the characteristics of the habitat were assessed in terms of trace element content and the pH and EC of the ash. A reduced vitality of all populations growing on the ash was observed, except for the naturally colonized A. fruticosa. High vitality on all sites, except at L2, increased chlorophyll content and absence of damage symptoms indicates a tolerance in relation to the uptake of toxic elements from the ash. Therefore, the characteristics of naturally colonized species can be used for modeling future actions of biological restoration of fly ash deposits.