The reserve ‘The Swamp of Wizna II’ is a strict peat-bog reserve with the surface of 76 ha. It is located south of the village Grądy-Woniecko. Till the time of reclamation nearby meadows there was a lowland peat bog with rare plant species such a thyme, a lasted marsh felwort and a low birch. Unfortunately, nowadays it became overgrown with birches and black alder trees.