Landscape Insight August 2017 | Page 66

THE LAST WORD MAX WADE Looking out for Giant Hogweed and avoiding its effects By Professor Max Wade, chairman of the Property Care Association’s ‘Invasive Weed Control Group arlier this summer we issued a warning to those in the landscaping and associated industries, urging caution with the invasive weed Giant Hogweed. The plant’s sap is extremely toxic to human skin in sunlight, making it a danger to public health. The PCA wanted to let people know that if anyone comes into contact with any part of the plant, followed by exposure to sunlight, they can sustain severe blistering to the skin and discomfort, which can become a long-term condition, recurring in subsequent summers. Once again, Giant Hogweed is turning out to be a summertime problem. It is continuing to spread and, in just one area alone, the chairman of our Invasive Weed Control Group, Professor Max Wade, reported seeing it appear in five new locations.  It is really important that the plant is spotted and that its toxic sap does not come into contact with skin in the sunlight. If this occurs, it can lead to a nasty rash, itching and blisters when skin first makes contact with it in sunlight. Worryingly, the rash and the itching can reoccur and flare up for years afterwards when skin is exposed to sunlight.  An added concern is the fact that an individual can come into contact with Giant Hogweed sap in cloudy conditions but later on the sun comes out, the photochemical reaction occurs and they are affected by blistering and a rash. Likewise, sap which comes into contact with items such as clothing and equipment, can also be transferred via touch - so it can possibly affect somebody else if their skin is also exposed to sunlight. For example, were a flail mower used to cut through vegetation including Giant Hogweed, E 66 Landscape Insight | August 2017 be cleaned after completing the work and the operative then goes out into the sunlight with sap on their skin, they too would be affected. It is this delay factor which makes detecting the source of the blistering and rash a difficult one. We’ve been made aware of a number of reports of people sustaining injuries after coming into contact with the invasive weed in the UK in recent years. The chemical in the plant, a furanocoumarin, needs bright light to react with the skin and causes blistering and other health problems, so this is the time of year when problems can ensue.  If you make skin contact with this plant or think you might have, cover the affected area from sunlight and as quickly as possible thoroughly wash any sap away, preferably with warm and soapy water. Visually, the plant’s stature sets it apart from the UK’s native hogweed. Giant Hogweed can grow up to 3 metres high with a 2 centimetre diameter stem and a large, white, umbrella shaped flowering head.  The general public, as well as local authorities, statutory agencies and landowners on whose property people can come into contact with the plant should be aware of the risks and Giant Hogweed needs to be controlled and managed professionally. Obviously, those in the landscaping industry also need to be well aware of the issue too and work to prevent the spread of this plant, a tall order given the thousands of seeds produced by a single plant. More details on the conference can be found at www.property-care.org