The impatiens downy mildew outbreak is seeing some suppliers cut production of Impatiens walleriana while others are recommending alternative plants to customers.
Growers are still offering impatiens but they are expecting sales to fall while sales of begonias and geraniums will rise instead.
Ball Colegrave has written to its customers advising on the situation with impatiens downy mildew and suggesting alternative varieties. Among these are New Guinea Group, which are resistant to the disease.
The company is still offering the full range of impatiens as seed, plugs and cutting-raised young plants in its 2012 catalogues.
Meanwhile, Earley Ornamentals has decided not to grow impatiens from rooted cuttings, which was the source of the downy mildew outbreak, but will be producing seed-raised plants.
"We are providing them if customers want them but we are anticipating a big drop in sales," said managing director Simon Earley. "We are saying that there are no sprays available for the present strain of mildew and suggesting that they grow other things. Some customers are saying they are not growing full stop, while others are growing less."
He added that this was an opportunity for other plants. "Begonias will be more popular and seed-raised geraniums have been good this year," said Earley. "Sales will increase for most plants at the expense of impatiens."
Pentland Plants owner David Spray added: "People are not going to order as much. Big planting people who have had real disasters will move over to begonias. It's frustrating because they were very cost-effective. I expect we'll lose two-thirds of impatiens sales."
Downy mildew - Seminar discussions
The Horticultural Development Company is holding a seminar for breeders, growers and retailers to discuss impatiens downy mildew at Stoneleigh Park in Warwickshire on 26 October.
Communications manager Wayne Brough said: "Growers and propagators are making decisions about 2012. The meeting is an open event to help people decide what to do. We are already seeing other species coming to the fore."