The business is for sale without its 4.5ha Chichester nursery, which is under offer to another grower.
THe Duncan & Davies brand, a 400-strong customer list which includes Marks and Spencer, expert knowledge and contacts, and £200,000 of stock, is on offer.
Tax losses of £1.12m are included in the sale.
The business is run by Ian Light and managed by Adrian Corbett.
It imports plants, particularly camellias, acers and magnolias, from New Zealand and South Africa and trades them on.
The company has developed red Pseudopanax and has crossed Camellia 'Bob Hope' and 'Ballet Dancer' as part of its plant development research.
Duncan & Davies began in 1898 in New Zealand. It exported to the UK and in the 1970s the New Zealand government chose the company to develop horticultural exports.
In 1983, Duncan & Davies (UK) was established in the UK, at Highleigh Nurseries in West Sussex.
Quinton Edwards is now seeking offers of £375,000 for the business.