Developers face a 'knotty' problem


Property developers across Northern Ireland are facing a knotty problem that threatens the local wildlife and has the potential to damage new buildings.

The culprit in question is a plant Japanese knotweed.

It is described by environmental consultants at White Young Green Ireland, as 'an ecological bully'.

The weed can cause extensive damage to buildings and is so much of a threat to the environment that it is illegal to cause it to spread in the wild.

It's such a problem to builders and developers that White Young Green is running training courses to help the industry get to grips with the invader. Dr Eleanor Ballard, senior ecologist with the consultancy firm explained - "Japanese knotweed was introduced by adventurous Victorian gardeners who soon realised that it had a nasty side.

"It is an ecological bully that causes extensive damage to buildings as it can grow through mortar and tarmac with ease. It's a real scourge to the natural environment too - blocking the sunlight from our native plants. If you cause it to spread in the wild, you are breaking the law. We are advising developers that its cheaper and less problematical to start dealing with the plant as early as possible in the development process."

New Japanese Knotwood plants become visible in early spring and emerge from the ground appearing red or purple at first.

They grow rapidly during the summer to a height of 2-3 metres.

Their leaves are shaped like a shield with a small pointed tip and are bright green in colour.

The stems are hollow with purple specks and the rhizome (an underground stem) under the plant is thick, woody and may have small red buds - each of which has the potential to grow a new plant.

In winter, the Japanese Knotwood leaves die back, but the dead stems persist and resemble bamboo-like canes. These are often a good tell-tale sign that there is a knotweed problem on a site.

Dr Ballard said the weed was difficult to kill off - "One application of weed killer will not solve the problem and we are working with a range of public and private sector organisations to identify the plant on their sites and produce management plans to assist in its removal.

"We've also introduced training courses to help developers understand the risks that knotweed can cause to their new buildings and development plans and we advise people working on sites how to identify and control Japanese Knotweed."