Giant Hogweed Eradication Programme

WHY?

Giant Hogweed represents a serious health hazard for humans. When the clear sap comes into contact with human skin on subsequent exposure to the sun it can cause severe skin burns - see this example. Blisters occur within a day or so and dense pigmentation occurs a week later. The skin may remain sensitive to ultraviolet light for years. So however appealing the flowers look don't pick them, and however great a stalk looks as a pea-shooter DON'T!

Giant Hogweed can form dense colonies. Its height and large leaf area forms a dense canopy out-competing natural, native vegetation. Overwinter die-back along riverbanks exposes bare earth resulting in an increased risk of bank erosion. We have enough of that just with fast flowing water!

THE Programme

Biology: Giant Hogweed (see Heracleum_mantegazzianum on Wikipedia) - GH for short - grows for a couple of years before it flowers, from June to August, and then sets seed; after which it dies. It only propagates by seed, but a single plant can produce 20,000 seeds. Only a few of these will germinate, and mostly nearby, but some may be swept down river, and thus start a new infestation. For more detail, see the Non-Native Species website

Where are they? Always (well, nearly) on the river bank. We are doing full surveys of the river and all its main tributaries: the Coulston, Birns, Humbie & Keith Waters. See where there all are on our Map page.

Who is involved? All the farmers along the river have agreed to be involved (thanks to the hard work and persuasive powers of our coordinator James Wyllie). And all the domestic property owners where GH has been spotted are also on board. It does need everyone along the route, as if we miss even one plant that has gone to seed, we are nearly back where we started.

How Long For? Seeds can lie dormant for 5 years or more, so we will keep this programme going for quite long time!

What Do We Do? We plan to find all the GH plants by the river and treat them. Either by:

spraying them in Spring, and again as we see them in Summer, before they flower
if already flowered we will also dead-head, as flowers can turn to seed
digging them up, if they are few, young & small

Other Invasives? Japanese Knotweed is also present. Farmers have the expertise to deal with this, although domestic landowners are actively discouraged (but do let us know!). Himalayan Balsam is also widespread, although less problematic, so we may tackle this in the future.

There are several strands to our programme: see Spotting, Spraying, and Supporting.

Spotting

We have around 70 volunteers who walk, cycle or even wade the river, and record any they see, using a GPS app on a mobile phone, and email us at (esk)hogweed@elcv.org.uk.

We publish all the sightings on our maps eg at elcv.org.uk/HogweedMapTyne in enough detail for all landowners to locate (see our Maps page). The Project co-ordinator can also make contact with the responsible landowner.

How do you identify a Giant Hogweed plant? See this NNSS Leaflet or the WildFoodUK website. It's very easy to confuse with Common Hogweed. And how do you identify Japanese Knotweed? Test yourself with our Quiz! Want to be a spotter? - See this presentation

Spraying/Digging

The quickest way to deal with a group of Giant Hogweed is to spray them with a weedkiller like Roundup.

Farmers
Usually have both the equipment, licence and experience to spray, and have kindly volunteered to add GH to their list of targets. Our project coordinator, local farmer James Wyllie, has prepared these notes targeted at all the farmers, and here is his latest newsletter.

Domestic Landowners
Are likely to have smaller infestations, and spraying near water requires permission, so it is better to dig them up - see below.

All
You can see all known plants on the map at //tinyurl.com/ELCV-THE-Map

Supporting

What is the cost of this whole programme? It is entirely run by volunteers, so there are no staff nor contractor costs!

The riparian landowners - now numbering around 75, mostly farmers - have all agreed to carry out the control at their own cost. Labour is conservatively estimated at £9000, and chemicals at £800, every year. A total of £100,000 over 10 years, which is an exceptional donation from them.

Bayer UK have again supplied some Roundup weedkiller to help the farmers which we distributed at our season-start meeting. Last year SNH gave us a financial donation, but unfortunately not again this year.

The ELC Countryside Service have also shared their data, advice and encouragement.

Domestic Treatment

With a very young plant, you can probably pull it up if the soil is moist
For a normal plant you need to dig it up, severing its roots. How? - see this video
If it has already flowered, you also need to dead-head it, bag the heads & remove from the area
If it has set seed, dead-head carefully to avoid seeds falling. Although you are probably too late!

Giant hogweed material is controlled waste so, if it is taken off site, should only be disposed of in licensed landfill sites - the green bin is typically OK. NOT the garden waste bin! Or you can burn in your own incinerator if you have one.

Protect yourself with gloves and long sleeves from any skin contact with the sap, and especially your face, when cutting stems. And best carry out the work in overcast weather to avoid sunny periods. Wash off any sap as soon as you can with plenty of cold water. And don't, like I did, take off your gloves and carry them in your hands (I had a small burn on my hand for weeks!)

2018....Some History....2024

In years past the council countryside team have occasionally organised volunteers to clear a number of young infestations. In 2018 we intensified our efforts and surveyed the Tyne from Haddington to the sea, and dealt with most of the GH we found. Nearly all were killed - either dug up if immature or dead-headed if flowering/seeded. Except in Tyninghame Estate where there were just too many!

And so we realised that with a concerted effort we could completely eliminate GH from the whole river, from source to sea, and the Tyne Giant Hogweed Eradication Programme was begun. The first task was to contact James Wyllie, a retired farmer, who had been the driving force behind successfully clearing GH from the length of the Biel & Whittingehame Waters (see the differences there over the years). Within weeks he had contacted all the farmers along our route and secured their agreement to this programme. Every year since, we've prevented any plant from flowering anywhere on the Tyne. So the seedbank is steadly reducing.

In 2022 James' daughter started an identical project on the River Esk. A much more daunting prospect. But we are making headway!