He is known for the use of stencils to create elaborate patterns and for decorating the interiors of World Heritage Site Gästgivars in Vallsta, Hälsingland.
[7] Wallström has painted several farmhouses in the central part of the Ljusnan valley, mostly in the regions of Bollnäs and Arbrå.
[4] Some of his works were signed, while others have been attributed to Wallström based on their style, including choice of motif and colours.
[4][9] The painted interiors of World Heritage Site Gästgivars in Vallsta are well preserved examples of Wallströms skill.
[6] Other works attributed to Wallström are exhibited at Hälsinglands museum,[7] Renshammar in Bollnäs, Wallins in Växbo, Lars-Pers in Hov, Träslottet in Koldemo and Arbrå Fornhem.
[4] At Wallins he restored decorative painting performed by Paul Hallberg[7] and completed a few works of his own in other rooms on the lower floor.