Any work using non-permeable products covering over 5sq m now requires planning permission.
But marketing controller Ian Wright of hard landscaping product supplier Bradstone said some aspects of the legislation were still unclear and that it might not fully come into effect until 2011.
Meanwhile, the RHS, whose campaigns have helped to bring in the legislation, has surprised observers by recommending only one paving product - Priora from Chelsea sponsor Marshalls - in its advice to gardeners.
"It is interesting that Marshalls is the only company mentioned. The RHS should try to be more impartial," said consultant Doug Stewart.
An RHS representative said: "Marshalls has been supporting RHS activities through show sponsorship since 2007, and during that time its range of permeable and sustainable products has increased, making them one of the most ethically minded hard-landscaping companies in the UK.
"We advise consumers to choose an environmentally friendly solution that meets their needs," the representative added.
A Marshalls representative said: "Permeable paving has been developed for this instance. Marshalls has looked at this for a long time as an opportunity."
A Bradstone representative said he has asked the RHS about the matter.
- Visit www.communities.gov. uk/publications/planning andbuilding/pavingfrontgardens
- See vox pop, p19
RHS'S TOP PRODUCTS
- RHS top surfaces for front gardens Gravel; permeable, weed-suppressing membrane; permeable paving blocks; grass with grass reinforcement; matrix pavers
- RHS top plants for front gardens Rosa Flower Carpet Coral, Salix caprea 'Kilmarnock', Salvia x superba, Pyracantha, Potentilla fruticosa.