Manager Anna Burtenshaw said: "It's the end of the line for me after 32 years with the company. It's a great loss and many customers are upset. It's the end of an era." There are six staff, with one being retained by Manor.
In March, developers David Wilson Homes and Barratts won an outline planning application for 32 homs on the garden centre site from Arun District Council, as part of the masterplan drafted by Arun and developers to provide 600 homes.
The garden centre's Facebook page has announced the closure for July 19. It said: "We would like to thank our customers for your continuous support, especially over these last few difficult years. We have appreciated the many kind words and the offers of help for now and the future.
"We all have enjoyed working here and will really miss it, but most of all we will miss you our loyal customers. A big thank-you from all the staff at Manor."
The garden centre is now holding a closing down sale and its collection of cacti will be transferred to the other Manor Nurseries site at Runcton, near Chichester.