Government proposals to relax planning regulations could mean less work for the landscape industry, BALI has warned.
Chief executive Wayne Grills said: "Private developers are notorious for cutting the landscaping budget at the end of a project and if they are not required by planning to deliver a certain level of landscaping they aren't going to do it from choice."
Intensification of housing at the expense of green space would also impact on landscaping, he added. "It is hoped that public realm schemes will be largely unaffected by any relaxation in the planning regulations as that would wreck the efforts of planners in recent years who have championed more green space in urban areas."
He said increasing development of brownfield land means landscapers must get to grips with the issues and regulations involved with working on contaminated sites. Brownfield sites surrounded by buildings may also have restricted access, which would push up contractors' costs.
Town & Country Planning Association chief executive Kate Henderson expressed concern about the proposed changes. "Without planning, Britain would look very different - we wouldn't have well-designed attractive cities, market towns and villages, green belt and national parks," she said.
"The decision to give automatic planning permission to sites on brownfield land seriously undermines the ability for genuine place-making."
Landscape Institute director Noel Farrer said development on brownfield is a good idea but to create places where people want to live long-term it needs green infrastructure at its heart.
The institute promotes a green infrastructure approach to design, delivering benefits across fields as diverse as public health, food and energy security and climate change mitigation.
Farrer explained: "Given the acute shortage of housing, quick-fix, poor-quality housing would sell, but it is dangerously short-sighted as we will pay a high price in the future through the creation of failed communities."
He added: "In the past we have demolished poor-quality housing. Whatever the pressure to build we must not sacrifice design quality and create substandard homes to become the slums of the future. A green infrastructure approach would deliver sufficient quantities of housing as well as creating sustainable places."
The institute wants the Housing Design Advisory Panel to investigate the proposals and the role of green infrastructure in creating new brownfield settlements.
Budget - Faster housebuilding prioritised
Chancellor George Osborne announced changes to the planning system aimed at speeding up housebuilding.
A key tenet of his plan is introducing a "zonal" system that would give automatic planning permission for building on suitable brownfield sites.
The relaxation of planning rules includes removing "unnecessary" obstacles such as "detailed and discretionary scrutiny" that make building slow and expensive.
In line with the Government's stated commitment to devolution, London and Manchester's mayors would gain planning powers.
But where local authorities have failed to produce local housing plans, the Government would override them and create a plan in consultation with the community.