Psychedelic music's LSD-inspired vibe began in the folk scene, with the New York-based Holy Modal Rounders using the term in their 1964 recording of "Hesitation Blues". The first group to advertise themselves as psychedelic rock were the 13th Floor Elevators from Texas, at the end of 1965; producing an album that made their direction clear, with The Psychedelic Sounds of the 13th Floor Elevators the following year.

Psychedelic rock particularly took off in California's emerging music scene as groups followed the Byrds from folk to folk rock from 1965. The Los Angeles-based group The Doors formed in 1965 after a chance meeting on Venice Beach. Although its charismatic lead singer Jim Morrison died in 1971, the band's popularity has endured to this day. The psychedelic life style had already developed in San Francisco since about 1964, and particularly prominent products of the scene were The Grateful Dead, Country Joe and the Fish, The Great Society and Jefferson Airplane.] The Byrds rapidly progressed from purely folk rock in 1966 with their single "Eight Miles High", widely taken to be a reference to drug use.

Psychedelic rock reached its apogee in the last years of the decade. In America the Summer of Love was prefaced by the Human Be-In event and reached its peak at the Monterey Pop Festival, the later helping to make major American stars of Jimi Hendrix and The Who, whose single "I Can See for Miles" delved into psychedelic territory. Key recordings included Jefferson Airplane's Surrealistic Pillow and The Doors' Strange Days. These trends climaxed in the 1969 Woodstock festival, which saw performances by most of the major psychedelic acts, but by the end of the decade psychedelic rock was in retreat. The Jimi Hendrix Experience broke up before the end of the decade and many surviving acts, moved away from psychedelia into more back-to-basics "roots rock", the wider experimentation of progressive rock, or riff laden heavy rock. (Wikipedia)