DEVELOPERS at the 276-home Ramshill site in Petersfield are facing a new challenge that could cause significant damage to roads and foundations on the proposed estate.

This time the opponent is one of the most invasive plants in the country.

Council officers discovered an area of Japanese Knotweed, measuring six metres by four metres, on the site earlier this year.

The weed can grow up to 10 feet high and is so aggressive that it can grow through asphalt, concrete, house floors and even house foundations.

John Beresford, senior land manager for Bryant Homes, said: ÒThe last thing any developer wants is Japanese Knotweed.Ó

Bryant, in partnership with consultants CPM, has produced a detailed eradication strategy and timetable to ensure that the weed is cleared from the site before development begins.

But the plan admits that there is Òno known guaranteed method for the eradication of the speciesÓ. The plan also states that the weed Òhas been known to grow through Tarmac and house foundations, causing significant damage to propertyÓ.

Discarded Knotweed is classified as Ôcontrolled wasteÕ under the 1990 Environmental Protection Act.

The 1981 Wildlife and Countryside Act made it illegal to spread the weed.

East Hampshire District CouncilÕs landscape officer Stephen DÕEste Hoare said: ÒThey [Bryant] will have to undertake appropriate measures as part of planning approval. We will be monitoring that work. The problem needs to be tackled early on.Ó

The eradication process will involve spraying the affected area and disposing of the waste material.

Mr Beresford said: ÒAt the moment we are looking at two ways to deal with it. One is burial on site. The other is removal off site to a registered landfill site.Ó

The weed spreads extremely quickly, usually from fragments of cut stem, and Mr Beresford said that workmen would be very careful not to disturb the affected land until the weed has been carefully removed.

He said: ÒYou only need a piece the size of a fingernail and it will develop quite quicklyÓ

Petersfield Town Council is currently considering taking control of green space on the site, once the development is complete, but is confident that the conditions of the planning application, as set out by EHDC, are sufficient to deal with the problem.

George Watkinson, chairman of Petersfield Town CouncilÕs planning committee, said that if the town council does take over the green space it would want EHDC to ensure that all conditions of the planning application, including the eradication of Japanese Knotweed, had been met.

Japanese Knotweed was introduced into this country in the 19th century as an ornamental plant and since then has spread rapidly. It is now a serious problem on many riverbanks, railway embankments and derelict land, but according to Mr DÕEste Hoare it has never been widespread in the Petersfield area.

Because it is not native, the pests and diseases that control it in Japan, where it grows in harmony with other plants, are not present in the UK.

It is a perennial weed that forms dense, tall canes during the summer months.

Mature canes are hollow with distinctive purple speckles. Creamy white flowers appear in late summer to autumn.

Martin Healy, arboricultural officer for EHDC, said: ÒIt is a weed that blocks out other plants because it is so strong. It is completely dominant.Ó