International Harvester only played together for three years, the first under another name, but they were an influential group for Swedish progressive rock. While making sonic experiments and deep excursions into psychedelic rock, their biggest contribution was probably that they were the foundation on which the more famous group Träd, Gräs och Stenar was built.
International Harvester started as the short-lived experimental group Pärsson Sound. The group formed in 1967 in Stockholm by guitarist Bo Anders Persson and included cello player Ericsson and violinist Yman, both with a musical education and playing on homemade electric instruments. Saxophonist Tidholm was a film student and a poet, drummer Gantz had played with the progressive dance orchestra Mecki Mark Men, and at times the band also included an extra drummer, Berger. Pärsson Sound was mainly an instrumental group and their music was not very accessible. At times they let a tape pass two tape recorders on stage, one recording and one playing, which meant the music returned, overdubbed and distorted in an increasing mass of tones and noise. They played a number of gigs at the club Filips, the main spot for progressive rock in Stockholm, and started to get more well-known after a festival in Kungsträdgården, where Don Cherry and Peps Persson also played. In 1968 they changed their name to International Harvester and abandoned the most extreme sonic experiments, instead putting the focus on folk music and psychedelic rock. Tidholm's vocals were allowed more space and in stressing the collective and improvising aspect, the band gave a hint of what would come with Träd, Gräs och Stenar a few years later. Living together in a collective, they made films and composed music, including the soundtrack for a few professional films. On Öjvind Fahlströms' Du Gamla du Fria, the band created and improvised all the music while the cameras were rolling.
The debut album Sov Gott Rose-Marie was released in 1968 on Love, a Finish label, since there were no Swedish alternative labels around and no commercial labels were interested. But already in 1969 alternative labels had started to pop up, and with the name shortened to Harvester the band released their second album, Hemåt, on Decibel. Later that year, Tidholm and Yman left. Tidholm formed Hot Boys but was to become most well-known as a poet and a writer of plays and children's books. The remaining members formed Träd, Gräs och Stenar and toured Scandinavia intensely for a few years, taking the idea of interactivity one step further by involving the audience in the music making. With a climate increasingly receptive for psychedelic music Träd, Gräs och Stenar were more successful than International Harvester, but otherwise they had much in common, building on elements of psychedelic rock, blues-rock, and folk music.