The independent charity has a pitch process under way for a roster of up to eight agencies.
The successful agencies will act as part of a panel of suppliers spanning eight areas of the organisation, including legal services, human resources and marketing.
The PR roster will be made up of a variety of regional and national agencies that will be employed to handle project work across the trust's portfolio. The body is calling for agencies with expertise in PR, public affairs and community engagement.
The aim of the trust is to provide long-term sustainable management of open spaces across the country. It was formed in 2004 as a subsidiary of English Partnerships.
Comms director Deborah Holmwood said: 'The brief is to promote the trust as a corporate entity - how we effect change and engage with policymakers - but also about highlighting the benefits of open spaces.'
Holmwood added that the agencies would also be asked to drive traffic to the trust's website.
A decision has not yet been made on fees, which will be decided during the pitch process. Appointments are expected to be made in mid-July, and the agencies will be in place for at least a year.
The Land Trust currently uses Smith & Smith for corporate press but handles regional and local press in-house.