HOME TRUTHS: THIS PLANT COULD DEVALUE YOUR HOME
Plants are a wonderful addition to any outdoor space. They aesthetically improve a home’s kerb appeal while also helping to encourage wildlife. Plants are great for your mental health and also help to create a relaxing outdoor space. However, there are certain plants that can be more menacing than relaxing. One plant that is a major issue is Giant Hogweed. This plant, in particular, can cut thousands off the value of your property.
So what is Giant Hogweed, and what can you do about it? Gardening and plants expert Calum Maddock at HomeHow.co.uk has created this guide, explaining everything you need to know about this invasive plant and what you can do to irradicate it. Read on to find out everything you need to know.
What Is Giant Hogweed?
Giant hogweed also known as Heracleum mantegazzianum is an invasive plant which originated in the Caucasus Mountains between southern Russia and Georgia. It was introduced into the UK in the early 19th century as an ornamental wetland plant.
Part of the Apiaceae family which includes carrots, parsley and parsnips this specimen is substantially bigger than its relatives. Fully grown giant hogweed can reach between 1.5 metres and 5 metres in height and can spread to a width of 1-2 metres.
The white flower heads which are held in umbels can be 60cm in diameter. Its leaves are very large, up to 1.5 metres wide and 3 metres long. They are lobed with jagged edges and form a rosette in their first year. The flower spike rises from the middle of the rosette.
The hollow stems are green and ribbed with purple blotches. They are covered in white bristles, which become coarser as they near the base of the plant.
Flowering usually takes place in the second or third year. Giant hogweed can behave like a biennial or perennial either dying back after flowering in its second year or coming back annually.
The large flowerheads of giant hogweed can produce thousands of seeds, which are spread by wind, water or human activity.
This invasive plant is now found along riverbanks, on disused ground and in gardens and allotments close to infected heathland and woodland.
Why Is Giant Hogweed Dangerous?
The sap in giant hogweed contains compounds called furocoumarins. When the sap comes into contact with the skin, these compounds prevent the skin from protecting itself from the sun’s UV rays.
This results in severe reactions when the skin is exposed to UV light, which is known as phytophotodermatitis.
Large rashes and blisters form within hours, and the effects can be painful and long-lasting, with scarring and recurrence very likely. If giant hogweed sap gets into someone’s eyes, it can lead to blindness.
Removing Giant Hogweed From Your Property
If you have giant hogweed on your property, you are not obliged to remove it nor are you obliged to inform anyone. However, most people choose to have it removed as it is so toxic.
You must not let giant hogweed spread to adjacent land. If this happens, legal action can be taken against you. You also have a legal duty under the Wildlife and Countryside Act 1981 to prevent the plants from spreading into the wild.
As giant hogweed can grow from its seeds, roots or rhizomes it needs to be disposed of carefully. For this reason, it is considered controlled waste and needs to be disposed of in a licensed landfill site.
Polluted ground material such as soil that giant hogweed has grown in is also considered controlled waste and must also be disposed of accordingly.
Methods of Removal
Plants can be eliminated by spraying, physical destruction, on-site burial or offsite disposal. The best solution will depend on the size of the plants, their numbers, and the extent of the infestation.
Spraying
Spraying should be carried out by a qualified professional who is experienced in the safe handling of herbicides. Glyphosate-based herbicides are considered the most effective, and all regulations and conditions for use must be met.
This method is best used in spring when plants are smaller but will have to be continued for several seasons.
Physical Destruction
Physical destruction of giant hogweed can be done with machinery such as a tractor-towed flail for large areas or manually for individual plants.
For manual destruction, full protective clothing should be worn to protect skin from sap exposure. When using machinery workers and bystanders should be protected.
Digging out the plant and severing the root should kill the giant hogweed which should then be left to dry out before disposing of it safely. This method is often used in conjunction with spraying with herbicide.
On-site Burial
For this method of removal, permission must be sought from the Environment Agency in England or the Scottish Environment Protection Agency in Scotland. Plants and seeds must be buried at least 1 metre below the finished ground level.
The burial site should remain untouched for 15 years, and the location has to be recorded.
Offsite Disposal
Taking giant hogweed, its seeds and the soil to a licensed landfill is the quickest way to deal with this toxic plant. All plants and the top 10 cm of soil will need to be removed, as will the soil in the surrounding area, to ensure all seeds have been removed.
The Environmental Protection Act 1990 makes it illegal to dispose of giant hogweed anywhere other than a licensed landfill site.
How Much Does It Cost to Remove Giant Hogweed?
The cheapest method of removing giant hogweed is by spraying while excavation and offsite disposal are the most expensive. Each situation will be different, and costs will also depend on the size and extent of the infestation.
It’s advisable to hire a company that is a member of the Invasive Non-Native Specialists Association to deal with giant hogweed to ensure complete peace of mind.
The price of having a specialist remove giant hogweed from your land will depend on the size and extent of the problem.
Survey Cost
A surveyor will conduct a Full Residential Invasive Species Survey on your property. Costs typically start from £300 + VAT (£360). This amount is payable prior to the surveyor’s visit.
The survey is a critical first step to ensure all invasives are identified and accounted for in any remediation strategy and subsequent insurance guarantee. It will normally include:
- A survey of the property with a trained surveyor.
- A full written report of findings.
- GIS mapped out the area with a 1mm accuracy (where possible).
- CAD site plan showing the location of Invasive Species in relation to property and property boundary.
- Full photographic evidence of the visit.
Quotation
You will then receive a quotation for an appropriate remediation method (if required).
Here are some service examples:
- 5-year Invasive Plant Management Plan (IPMP) – dependant on survey findings but potentially ranging between £1,900 + VAT (£2,280) – £2,500 + VAT (£3,000) for a small invasion.
- A typical chemical treatment for a small infestation of less than 30 sqm can cost around £2,000 + VAT (£2,400) -£4,000 + VAT (£4,800).
These prices can increase when looking at more severe cases of giant hogweed invasions.
Companies tend to price each project on a site-specific basis as each situation will be different. To get an accurate cost for removing giant hogweed from your property you will need to contact a specialist company, have a survey done and get a quotation.
Final Thoughts
While Giant Hogweed may seem like an innocuous addition to your garden, its dangers and legal implications for allowing it to spread make its removal a necessity for any homeowner. The cost of professional removal may seem daunting, but it pales in comparison to the potential devaluation of your property and the risk of harm to yourself or others. By taking action now, you can ensure the safety of your loved ones and the value of your investment.
