Why is Japanese knotweed a problem​?

If you are a keen gardener, you'll already be aware of the problems and frustrations of dealing with plants that grow quickly and take over the garden. 

For a homeowner, the problems caused by these invasive plants, such as bamboo, buddleia and Japanese knotweed, can be exasperating because it's not always clear whether the whole problem has been resolved, especially if the problem is inherited from homes and other areas that neighbour the property.

The Royal Horticultural Society (RHS) describes Japanese knotweed as “a weed that spreads rapidly”, and which dies back in winter but spreads from their underground rhizomes to push new growth in the warmer seasons. It is this underground spread that becomes the problem for homeowners, because the shoots grow to a height of over 2 metres and suppresses all growth of the other plants in its vicinity.

Specifically, the effect of this rapid growth is that it can damage and lift concrete and other building materials and cause serious problems with other hard structures within a building, such as walls and floors.

There are also cases where homeowners have brought in gardening firms to dig up their garden in an attempt to get rid of it, only to find that it returns soon afterwards, so pernicious is the method of propagation for this plant.

For this reason alone, it is a critical issue for prospective homebuyers - and, by association, for the vendor who wants to sell their property on. It is vital that the homebuyer is aware of the position with respect to Japanese knotweed, which is why the TA6 conveyancing form (more commonly known as the Property Information Form) now has a section on it where the seller must state whether Japanese knotweed is present within 3 metres of their property. 

The TA6 form is a legally-binding document, which means that a buyer has legal - and possibly financial - recourse if their response is found to be incorrect. So, the seller can only indicate “no” in the situation where they are positive that the plant is nowhere near their property.

There are specialist firms, such as Environet, which can provide an detailed analysis on the existence of Japanese knotweed at a property for a fee, which gives the seller peace of mind when it comes to filling in the TA6 form section truthfully and completely, while the buyer will have that clarification of the position to help in deciding whether to go ahead with putting in an offer.

Environet has also developed a Japanese Knotweed UK Heat Map, which gives a visual representation of where the problem is worst in the country. If you are buying or selling in one of the problem areas, this will give you the direction as to whether a full-blown report is required or not.

Homeward Legal always advises a buyer to take out a RICS Survey that goes into more details about the structural integrity of a property. The survey will include an assessment of any noted damage that might be caused by the proliferation of invasive plants. If there is sufficient concern and evidence, they may suggest the wisdom in getting a more detailed and professional report.

Environet has also reported recently that there are several outstanding misrepresentation cases - where buyers have subsequently found a problem with Japanese knotweed once the property has been completed and are in the process of trying to recover the costs of removal, treatment and legal fees as they fight the seller. The problem also has an impact on the saleable value of the property.

As the article states, 15% of sellers in a YouGov poll suggested that they would not be prepared to admit to the existence of Japanese knotweed on the TA6 form, or take any remedial action, which indicates the potential for a problem brewing later on.

The issue is particularly acute right now as buyers rush to take advantage of the lower stamp duty before the increase in April 2025. Because the Japanese knotweed is dormant in the winter months, the buyer will only become aware when it flourishes in the spring - after they have completed on the purchase.

If you're searching for a quality conveyancing solicitor who will work hard to bring your completion in as early as possible, look no further than Homeward Legal. 

Our conveyancers will start work on your planned purchase as soon as you agree to the quotation and appoint them to represent you. 

Homeward Legal will also provide a quote that will not change - what you are quoted is what you pay for standard conveyancing process, which means you can effectively budget for your conveyancing needs.

There are some unforeseen items that might arise during the purchase and/or sale, which includes a specialist flood assessment report, but the solicitor discusses these and their cost as they come up. 

In addition, to protect the homebuyer further, Homeward Legal operates a ‘no completion, no fee' promise, which ensures that, should the purchase or sale not go through as planned to completion status, no payment is required.

Call  to get your conveyancing quote started, or to discuss your concerns with your plans to move.

Or you can get a quick quote, using Homeward Legal's easy-to-use quote generator.