ELF Trust, Harewood, Calstock

Giant Hogweed Removal

Removal of Giant Hogweed on land managed by the ELF trust,
mainly comprising some 8 to 9 acres of SSSI.

The site is situated on the Cornish (western) bank of the River Tamar, 500 meters west and 700 metres north-east of O.S. Grid Ref: 452690

With co-ordination and funding, from English Nature and The Environment Agency, the River Tamar is being cleared of Giant Hogweed. The bulk of the work is being undertaken by 'Sylvanus' using glyphosate, possibly the Roundup concoction.


To maintain an organic integrity, the ELF part of the SSSI is being cleared by hand.

Giant Hogweed(Heracleum mantegazzianum) is a native of the Caucasian Mountains between Russia and Turkey, reportedly, introduced into the UK for ornamental purposes in the late 1800's.

Giant Hogweed's density and lack of persistant and binding root structure contribute to bank errosion.

Highly Irritant,


The sap of the freshly cut stem and leaves
- in the presence of sunlight -
is highly irritant, and
causes large blisters.


Many of the mature plants that had their flowering heads removed and stems cut to the ground, have sprouted new growth, producing up to 6 new flowering heads. (Note from 2002)

Giant Hogweed

Plots 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
1 to 8 2315 1123 268 104 49 22 16 2 5 1 0
A to H 1572 2588 3267 1691 567 201 250 112 50 25 7
Non SSSI 8 334 191 76 53 28 30 2 6 5 2
Totals 3895 4045 3726 1871 669 251 276 116 61 31 11

2012 Five looked like second yearlings

2011 Found one large plant, about to flower in plot A

2010 Have found a two plants in the western marsh boundary ditch, so I have extended Plot F to include this ditch. There have on other occasion been a couple there which have been recorded otherwise.

Found one large plant, about to flower in plot 5, and a few pretty big plants in the western fen meadow.

2008 Have found a few rather large plants in the 'compost field'. They must have been there last year??

Download details and map ghogweed.xls 369Kb

For details from 2013

Last Updated 24th July, 2018