Sandwort. Very classy alpine, like a refined Cerastium. Large white flowers cover the compact green mat of leaves. Not at all invasive. Needs good drainiage. Arenaria montana, the mountain sandwort, is a species of flowering plant in the family Caryophyllaceae, native to mountainous regions of southwestern Europe , from the Pyrenees to Portugal. The Latin specific epithet montana refers to mountains or coming from mountains Zone 3.