Henry and Charles Robinson are the sixth generation of flower growers on their 147 year-old farm which supplies sunflowers and sweet Williams for Waitrose.
During the summer, 60% of the flowers Waitrose sells are sourced from British farms, Waitrose said. Its campaign began with Father's Day and continues through annual British Flowers Week (19-25 June).
The Robinsons run their farm which has 420 acres of sunflower fields, with their father Richard, producing eight to nine million sunflower stems a year.
Waitrose horticulture buyer Lucy Matthewson said: "Sunflowers are a true sign that summer is here and we're lucky to work with such dedicated British growers to offer our shoppers an abundance of homegrown flowers."
Sunflower grower Henry Robinson said: "Growing flowers for us is not just a job, it's a passion. We never get bored of seeing our fields of sunflowers. We pick the stems when they are five to six feet tall and by the time they arrive at Waitrose, they'll be ready to open, showing off their magnificently cheerful yellow colour."