Paul Power's Starting Your Own Gardening Business: An Insider Guide to Setting Yourself Up as a Professional Gardener is a comprehensive introduction to setting up on your own.
Annie Meachem writes a monthly ezine for garden designers and landscape architects, focusing on business development strategies and developing a community. Back issues of the ezine are available at her website.
If you have come across any other useful resources for developing garden designer or landscape architect businesses, such as books or websites, please let me know by emailing resources@business-plans .co.uk.