Wingspan c. 10 to 13mm.

It inhabits river banks, ditches and the margins of streams.

Adult moths fly from evening into the night, and are on the wing typically in June and July.

The larvae feed on Water Mint (Mentha aquatica) and Gypsywort (Lycopus), living inside the stem, inside which they overwinter.

This species is locally common in southern parts of England, with records ranging northwards to Lancashire and Yorkshire, and North Wales. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

It appears to be uncommon in Leicestershire and Rutland, where there are few records. L&R Moth Group status = D (rare or rarely recorded).