Mark Gregory spoke out against the "continued and disproportionate" treatment of landscapers following the latest round of talks last week.
The talks included the Horticultural Trades Association, the British Association of Landscape Industries, Turfgrass Growers Association and seven utility firms.
The industry is calling for exemptions from the ban for professionals in areas such as the laying of new turf and plants. Water companies are refusing to budge.
"The water restrictions are potentially crippling for the landscape industry and a lot of people are very worried now. Landscapers have been victimised. This has not been thought through at all."
He highlighted the inconsistency of allowing car-wash and window-cleaning businesses to continue to use hosepipes but not landscapers on turf and plants on non-commercial sites.
During last week’s talks Thames Water suggested providing landscapers access to non-potable water.
But tanking in non-potable water and using drip-irrigation systems were not practical options for the turf industry in most cases, said Gregory.
Landscape contractor Adam Frost told Horticulture Week:
"I’m advising clients not to plant expensive stock until September or October, which means we will be running around like clowns with a backlog of planting.
"One of the key issues is to understand the full extent of the bans because they are not always that clear. I’ve heard some companies allow you to use porous hosepipes, but it’s not advertised. It’s up to landscapers to find out where they stand."