The GMB has stepped up its campaign for union recognition for Eastern European flower pickers.
The union staged protests outside the main entrance to the World Flowers packing plant in Hampshire, and another company site in West Sussex.
The GMB, which represents about 350 migrant flower pickers, is calling on the company to open talks on recognition.
World Flowers is a member of the Ethical Trading Initiative, working with individual suppliers to increase their ethical standards.
The company imports about 280 tonnes of fresh flowers a week and supplies major retailers.