Timpson said no deal had yet been struck: "I've made no arrangements with anybody regarding passing over our crops.
"I'm in discussion with a number of nurseries about that but nothing is finalised yet."
In a letter sent to customers at the end of last month, Timpson said: "Despite a large number of enquiries and a significant number of viewings, at this point in time no buyer has come forward, even though the nursery has been consistently profitable and remains a viable business with an enviable customer base and an excellent reputation for quality and service."
The letter continues: "Unless a buyer appears in the very near future, we have decided that the nursery will close at the end of September 2008. This clearly has implications for our customers and is a hugely difficult and traumatic situation for our staff."
Timpson said that trading will continue as normal throughout 2008. Plants already in production for 2009 will be sold by Hewton in August/September this year or transferred to other growers.
Cornish nursery Kernock Park Plants is one of the nurseries keen to take on the varieties currently grown by Hewton.
Managing director Bruce Harnett said the two companies have not yet met to agree if varieties can be taken on. "We are still in talks. Nothing's been absolutely finalised," said Harnett. "The varieties they grow would fit in with us quite nicely. We very much hope to be taking on growing their varieties."
He added: "Obviously, we are excited about the potential. The company is continuing to grow and expanding the Kernock range."