RICS Draft Guidance Note: Japanese knotweed and residential property, 1st edition


Included in this glossary are both terms referred to in the guidance note and other commonly used terms that the valuer may encounter when undertaking desk research or investigations to support residential valuations.




Tall, hollow, bamboo-like stems.


The visible part of the rhizome from which canes grow. Crowns can produce many new canes and because of their size, can be resistant to burning or drying out.

Environmental Protection Act 1990

Part II of the Environmental Protection Act 1990 (EPA 1990) contains a number of legal provisions concerning 'controlled waste'. Although Japanese knotweed is not specifically mentioned in the Act, any soil or plant material contaminated with Japanese knotweed that a person discards, intends to discard or is required to discard is likely to be classified as controlled waste. The most relevant provisos are in sections 33 and 34 of the Act.

Japanese knotweed

The common type of Japanese knotweed is known as Reynoutria (formerly Fallopia) japonica, but there is a smaller compact variety called Reynoutria japonica var. compacta, which reaches a height of 1m. Giant knotweed (Reynoutria sachalinenesis), can grow up to 5m and a hybrid between Japanese knotweed and Giant knotweed, Reynoutria x bohemica, is also found in the UK. For all practical purposes there is no distinction made in dealing with the different varieties. For the purposes of this guidance note 'Japanese knotweed' refers to all types of Japanese knotweed.

Registered Valuer

An RICS member who is subject to the quality assurance mechanism that monitors all

RICS members who carry out valuations within the scope of RICS Valuation - Global Standards (Red Book Global Standards) in order to ensure consistent standards.

Residential practitioner

In the context of this guidance note, residential practitioner refers to RICS members involved with advising their clients about all types of residential property.


Underground stem which enables Japanese knotweed to survive over winter when the canes die back. Small sections of rhizome, as little as 0.7g can regrow into a new plant.


A growth of plants in a particular area, a term which is not specific to Japanese knotweed. Stands can be small, large, dense, sporadic, etc., and the term is frequently used in descriptions of Japanese knotweed infestations.