Wingspan 16–24 mm. A very distinctive species with unmarked, uniformly bright green forewings and gray hindwings. The wings have whitish fringes on the edge.

Eggs are laid in pairs in the crown of the host tree.

Up to 18 mm. The head varies in color from brown to black and the prothoracic shield varies from near-translucent to black. Darkened pinacula, which are more prominent near the anterior end of the abdomen and on the thorax. Black thoracic legs and an anal comb with eight teeth.

Sometimes the larvae can completely defoliating the crowns. After clear-eating of his natural host plant, larvae disperse and attempt to feed on other deciduous trees. In the first two stages, the larva is feeding in young buds, later rolling the leaves. The eggs hibernate.
The adults can also be found resting in sunshine and are active from dusk onwards and come to light.

The larva lives mainly on Quercus with a preference for Quercus robur. Other food plants mentioned in literature are Vaccinium, Urtica, Acer, Carpinus, Fagus, Populus, Salix and Prunus armeniaca.
The species can cause extensive defoliation of oak trees.

Present wherever oak occurs.