The discovery of highly-damaging Japanese knotweed at the City Cemetery will not jeopardise plans for 1,000 additional burial plots, Derry City Council has claimed.
It has now been confirmed that there have been 11 outbreaks of the invasive knotweed, giant hogweed or Himalayan Balsam on publicly-owned sites, including at City of Derry Airport and the Culmore landfill site.
A further 24 infections at privately owned sites have been identified across the city.
Japanese knotweed can tear through pavements, roads, concrete and the walls of buildings; can block drains and is also considered highly dangerous for local biodiversity.
It is extremely difficult to get rid of once it takes root.
Contaminated vehicles or equipment can spread the weed, as can illegal dumping, and colonies of the plant can be washed along waterways.
A spokeswoman for Derry City Council said that it was first discovered in the City Cemetery two years ago and efforts to destroy it have been ongoing.
She added, however, that this would not halt work to increase capacity at the city’s largest graveyard.
She said: “Derry City Council recently awarded a tender for the development of the lower south east corner of the cemetery.
“Works are due to commence later this month with completion in late 2012, resulting in over 1,000 additional burial plots.
“Any knotweed within the cemetery is outside the area of these works and should not hinder the progress of the works.
“The knotweed has now had two years of eradication treatment, which will continue until the plant has been completely destroyed.”
Derry City Council has now set aside £25,000 to deal with the biohazard over the next five years.
All 11 public sites have been surveyed, with management plans produced and control programmes implemented on priority sites that are scheduled for development in the short term.
Japanese knotweed is native to eastern Asia. Despite this it has become increasingly successful at invading parts of Europe and America. It is notoriously difficult to treat as its complex root system means that off-shoots can appear several metres from the parent plant. Even a tiny piece weighing just 0.7g can rejuvenate itself into another plant.