He is known for speaking his mind and sticking to his guns. So when Monty Don described begonias as ‘repulsive’ on prime-time TV, his comments were bound to raise eyebrows.

Speaking on BBC2, during a thread entitled ‘plants you love to hate,’ BBC Chelsea Flower Show coverage host Monty said: “I hate a plant because it is repulsively ugly – and that’s the begonia. Don’t tell me that anybody likes begonias?”

Sensing trouble, co-host Joe Swift hit back: “You are going to upset many people. Millions of people love begonias and grow them in their greenhouses. There are begonia fanciers up and down the country.”

But Monty’s comments did upset growers, many of whom have invested thousands of pounds in promoting begonias as an alternative to Impatiens walleriana, the bedding busy Lizzie, which has been devastated by impatiens downy mildew in recent summers.

Thompson & Morgan has seen its begonia sales rise by 22 per cent in the last year. Horticultural director Paul Hansord said:

“I was amazed to hear Monty’s comment. He has lost touch with the gardening public. Begonias are T&M’s and many other companies’ top-selling bedding plant.

“Sales grow year-on-year because of their outstanding performance, whatever the weather. Minimum maintenance is required. There is a range to suit everyone, from bedding to baskets and patio pots.”

Mr Fothergill’s told AG that its sales of begonias had increased by 61 per cent this season. Brand manager Katherine Watt said: “Many of our customers do not share Monty’s dislike of begonias, and sales increases this season underline the point.

“There have been excellent introductions in recent years, and one of these, our Illumination Apricot Shades, is popular. It flowers for months on end.”

Head of horticulture at garden centre group the Horticultural Trades Association (HTA), Raoul Curtis-Machin, also disagreed with Monty. He said: “Sales have been on the increase as a result of begonias’ growing and enduring popularity with the public.”

Raoul added: “Begonias are great garden plants. They include fabulous bedding plants like the new Big series, featured in the Sun Flower Square garden at Chelsea.”

The BBC pointed out that Monty interviewed Lynne Dibley, of begonia specialist Dibleys Nurseries, the next evening. In the report, Monty admitted he had been “rude” about begonias and praised Lynne for her Begonia rex.