Ikebana has been practiced for more than 600 years. It was brought to Japan by the Buddhist priests in the 5th Century and was developed from the Buddhist ritual of offering flowers to the spirit of the dead. By the middle of the 15th Century, with the emergence of the first classical styles, Ikebana achieved the status of an art form.
You can read more about its history at the following links:
Or you may want to access the resources available at the National Agricultural Library.