The Rt Hon Lord Smith of Finsbury said he would be urging Environment Agency staff to read the campaign's report, Local Authorities' Commitment to Urban Planting, and get on board.
"The Environment Agency supports the use of planting as part of sustainable development because, as indicated by the report, planting brings environmental and social benefits to communities," he said.
"In support of the Greening the UK campaign, I propose to promote the report to our staff as a topical green issue through our website."
The report - which was endorsed by Communities & Local Government secretary Hazel Blears in a foreword - found that more than two-thirds of councillors noted developers had not delivered planting commitments outlined in approved planning documents.
Almost a quarter of respondents said this was a frequent or very frequent occurrence.
In addition, 56 per cent of respondents noted that their council either "never" or "very rarely" undertook site inspection to ensure developers upheld the terms of planning approval.
Planning Officers Society sustainability committee chairman Stephen Tapper said: "Greening the UK provides a great opportunity for planning officers to review their end-to-end policies and practice around urban planting and landscaping with a view to achieving more sustainable schemes.
"This should include the use of borough-wide open space and landscaping strategies in the context of the Local Development Framework, and masterplans and planning briefs, to achieve high-quality and relevant landscaping schemes at the planning application stage."
The HTA plans to step up the campaign in the coming months with an amenity guide produced by environmental adviser Chris Baines, along with training sessions for local authorities.
HTA director general David Gwyther said he was encouraged by the support from the Environment Agency. He said: "There are many synergies with the work of the Environment Agency and other agencies, and their endorsement is vital in helping us to raise awareness of the issues with MPs, councillors and other decision makers."