Giant Hogweed
We do have a problem with Giant Hogweed at the allotments.The hogweed is sprayed to kill it but in the growing season it can romp away if not controlled. We are looking at alternative ways to control it as well as weedkiller. The information below is to help you deal with it should you find one in your plot which you should deal with or decide that you would like to deal with one that may be near your plot. The main problem with Hogweed is the sap. More information follows below. There is also a slideshow which will help you to identify it as it is growing
My personal experience of hogweed is that it is best to dig it up when it is a small plant. If you do this then it is easy to get the whole plant up including the root.. I have also found that chopping off the root at the base with a sharp spade seems to work. The areas that the hogweed colonised at the allotments has been turned into growing plots this year. This should help control the plant as the new plotholders cultivate these areas. You will see from the information below that the best form of control is to cut off the leaves with a sharp spade beneath the soil to damage the root.
Always wear gloves when dealing with Giant Hogweed and do not let the sap or plant touch or spash onto your skin.
Treating with Weedkiller can also help eradicate this plant. Check on the label to make sure that it will kill hogweed before purchase and follow the instructions carefully.
If you find one in your plot please tackle it when it is small. If left it will grow into a huge plant very quickly. You can see the one in the picture is larger than the Wallace monument!
Giant Hogweed
Heracleum mantegazzianum Sommier & Levier, was introduced into Britain in 1893 as an ornamental plant. It escaped from domestication and is now colonising many areas of waste land and river banks. It can grow to 5m high and has a large umbel of white flowers from which it produces 30 to 50,000 viable seeds per year. When these seeds fall into water
they are dispersed downstream and washed up along the bank, often on scoured bare sediment, allowing the plant to spread rapidly along watercourses. In a natural state, the plant is biennial, growing from seed in the first year and flowering in the second season. However, if the plant is cut down before it produces seed, it will survive into a third or subsequent season, attempting to flower each year. It can form dense colonies which suppress the growth of native plants and grasses and leave the banks bare of vegetation in the winter. These are then liable to
erosion or to recolonisation by seeds of Giant Hogweed washed downstream onto the bare ground.
Cutting before flowering will, at best, produce only temporary control and
ensures that the plant regrows in the following season. Cutting after flowering has no benefit once the seeds have been formed, except to clear away the dying vegetation. Small infestations can be controlled by digging out the whole plant. It is possible that large infestations may be controlled by deep cultivation (ploughing) although this has not been tested and is generally impractical on river banks. Cutting through the stem must be done below ground level to ensure damage to the rootstock and to prevent regrowth from the base.
WARNING
The sap of giant hogweed contains a toxic chemical which sensitises the skin and leads to severe blistering when exposed to sunlight.
THIS REACTION CAN RECUR FOR MANY YEARS
.
My personal experience of hogweed is that it is best to dig it up when it is a small plant. If you do this then it is easy to get the whole plant up including the root.. I have also found that chopping off the root at the base with a sharp spade seems to work. The areas that the hogweed colonised at the allotments has been turned into growing plots this year. This should help control the plant as the new plotholders cultivate these areas. You will see from the information below that the best form of control is to cut off the leaves with a sharp spade beneath the soil to damage the root.
Always wear gloves when dealing with Giant Hogweed and do not let the sap or plant touch or spash onto your skin.
Treating with Weedkiller can also help eradicate this plant. Check on the label to make sure that it will kill hogweed before purchase and follow the instructions carefully.
If you find one in your plot please tackle it when it is small. If left it will grow into a huge plant very quickly. You can see the one in the picture is larger than the Wallace monument!
Giant Hogweed
Heracleum mantegazzianum Sommier & Levier, was introduced into Britain in 1893 as an ornamental plant. It escaped from domestication and is now colonising many areas of waste land and river banks. It can grow to 5m high and has a large umbel of white flowers from which it produces 30 to 50,000 viable seeds per year. When these seeds fall into water
they are dispersed downstream and washed up along the bank, often on scoured bare sediment, allowing the plant to spread rapidly along watercourses. In a natural state, the plant is biennial, growing from seed in the first year and flowering in the second season. However, if the plant is cut down before it produces seed, it will survive into a third or subsequent season, attempting to flower each year. It can form dense colonies which suppress the growth of native plants and grasses and leave the banks bare of vegetation in the winter. These are then liable to
erosion or to recolonisation by seeds of Giant Hogweed washed downstream onto the bare ground.
Cutting before flowering will, at best, produce only temporary control and
ensures that the plant regrows in the following season. Cutting after flowering has no benefit once the seeds have been formed, except to clear away the dying vegetation. Small infestations can be controlled by digging out the whole plant. It is possible that large infestations may be controlled by deep cultivation (ploughing) although this has not been tested and is generally impractical on river banks. Cutting through the stem must be done below ground level to ensure damage to the rootstock and to prevent regrowth from the base.
WARNING
The sap of giant hogweed contains a toxic chemical which sensitises the skin and leads to severe blistering when exposed to sunlight.
THIS REACTION CAN RECUR FOR MANY YEARS
.
