Jim Reid, sales director at Moles Seeds, said: "Jill has been well known in the industry for producing quality plants, attending trials over the years and operating the farm shop.
"Over the years Jill has raised many thousands of pounds for the RNLI and the local air ambulance, which are very important causes for her."
Hortors Nurseries, which will close at the end of March, is well known for hanging baskets, herbaceous borders and bedding plants. The farm shop sells locally produced fruit and vegetables.
Jill Horton could not be contacted.