In a series of studies, Colorado researcher Dorothy Retallick chronicled the effects of different types of music on potted plants. She found that when plants were exposed to jazz and classical music they reacted by leaning toward its source by up to 20 degrees during a two-week time span.
Exposure to three hours a day of rock music produced the opposite effect, The plants stretched and grew away from the source of the sound. Acid rock weakened and stunted their growth and they began to appear sickly, Marigolds died within two weeks of exposure while their classical counterparts thrived and flowered.
Retallick published her results in the book, The Sound of Music and Plants. She concluded that it wasn't so much the genre of music played that evoked strong plant reactions, but rather the types of instruments used and the particular sounds and tones they resonated. If it can be said that plants have a musical preference, they reacted the most positively to Indian classical music, leaning against the speakers at the sound of the sitar. Plants were "indifferent" to country and western music, showing no reaction.
Retallick concluded that exposure to the loud frequencies of certain instruments wreaked havoc on a plant's health preventing them from growing and thriving.