North Yorkshire Police said a man, who was wearing a white shirt, pulled the leylandii spiral plant out of a pot at the end of Baxtergate, before dragging it around the town centre..
The three-foot tall plant had been growing in the council-owned pot for five years before it was uprooted and stolen.
The incident happened just after 1am on Saturday May 6, but police only released details today.
Police have issued a CCTV still of a man they would like to speak to in connection with the theft.
A North Yorkshire Police spokesman said: "Police are appealing for information after a mindless vandal damaged and stole a large plant from a display in Whitby."
Anyone with any information about who is responsible for the theft, or who recognises the man pictured in the CCTV image, is asked to contact North Yorkshire Police. Call 101, select option 2 and ask for PC David Laverick or Whitby Police, quoting reference 12170080297.