While best known for his Irish landscapes, Verling also painted in France, Italy and Spain. His paintings comprise a concentrated pictorial account of particular areas of the south-west and west of Ireland.

His closely observed studies are acutely responsive to the nuances of light and atmosphere, reflecting an adherence to an underlying vision and a set of values that are rooted in a realist tradition of European landscape painting. He cites the French painter Camille Corot as the artist whose approach, above all, accords with his own feelings.