“Hartgen does not try for literal representation in his work. Rather, he depicts the quality and emotional impact of what he sees and loves: the explosive power of waves pounding against a mass of rock; silver birches silhouetted against deep pine forests; lichen growing on old trees; scudding clouds and stormy skies; traceries of branches against a winter snow. Hartgen’s work at its best combines the formal values of abstraction with a lyrical and romantic identification with nature.”
~ Leslie Judd Alexander, The Washington Post, 1959