ADVICE NOTE
                INVASIVE WEED                                            W:
                CONSULTANCY SERVICES                                     E:
                                                                         T: 01202 831151


This advice note aims to help anyone involved              Accuracy is most important, particularly if
with invasive weed control and in particular               invasive weeds have been contained
Japanese Knotweed. At PBA Solutions we                     using root barriers, as there is a residual
specialise in providing technical expertise in             risk that the root barrier may get
the control of invasive weeds, enabling our                disturbed, rendering them useless as a
clients to implement the most appropriate                  control method.
control method and achieve best practice
throughout the control programme.                          Surveying using GPS data collection
At PBA Solutions we operate in several ways:
                                                           We recommend that landowners such as
• Fully implemented by PBA Solutions under                 councils, rail networks and highway
  contract.                                                operators      record    invasive weed
• PBA led solutions, PBA undertake Surveys,                locations using GPS data collection. If
   complete Management Plans and provide                   you have a number of invasive weed
  site supervision through qualified Clerk of              stands that need treating over a vast
  Works.                                                   area, the utilisation of GPS data
• Specialist services including root                       collection is very efficient. At PBA
   barrier installation and herbicide                      Solutions we have experienced GPS
   application are routinely completed by PBA              Surveyors who can map & treat invasive
   Solutions.                                              weed with herbicide at the same time.
• PBA solutions sell a comprehensive range                 Once mapped herbicide technicians can
    of root barriers.                                      efficiently locate invasive weed stands
• Clerk of Works only – PBA act as a                       using GPS or Satellite Navigation at a
   watching brief.                                         later date. In short, PBA offer a very
• Skilled labour (we can provide skilled                   efficient and effective survey & control
  labour to install root barrier, apply herbicide          solution!
  or supervise excavations).
                                                           Ground penetrating Radar (GPR) &
The following pages introduce some of the                  Invasive weeds
consultancy services that we can offer.
                                                           At PBA Solutions we are able to offer
Surveying                                                  Ground Penetrating Radar (GPR) to
                                                           map root growth. GPR is like a virtual
We suggest that any invasive weed control                  excavator. We all have a responsibility
solution starts with a survey. It is fundamental           when we excavate and there can't be
that the location of invasive weeds is                     anything better than knowing what is
accurately plotted. There are also many                    below the ground before excavating. It is
benefits from accurately plotting the location of          also possible to locate services, badger
invasive weeds. If land is sold, it is important           sets, review root barrier locations and
to document the location of invasive weeds or              underground services. At PBA Solutions
where they have been treated.                              we don't leave anything to chance.

          For more information call PBA Solutions on 01202 831151, visit:
                                   or email

                                                                              Consultancy services 3/12/08
 Page 2                                       Invasive Weed Consultancy Services

Knotweed Management Plans/Invasive                       It is vital that landowners are furnished with
 Weed Management Plans                                   information that highlights these issues. At
                                                         PBA Solutions we combine KMP's
At PBA Solutions we promote the use of                   with Operation & Maintenance Manuals to
Management Plans and in particular                       provide documentation required for building
Knotweed Management Plans (KMP's). The                   manuals, which are necessary to comply
Environment Agency suggest that KMP's are                with building regulations.
'essential' and are an integral part of any
Japanese       Invasive     weed     control             Site Hygiene Plan
programme. In addition our consultants can
undertake the role of Clerk of Works so that             On a development site it is paramount that
KMP’s can be implemented as per the                      everyone associated with the site
Environment Agency Code of Practice for                  understand what Invasive weeds look like.
controlling Japanese Knotweed 2006.                      Often a development starts with good
                                                         intentions, in that people are confident that
KMP's bring together important information               invasive weeds will not be disturbed. Our
to which a landowner must have access,                   experience shows that in most cases
both during and after invasive weed control.             invasive weeds get disturbed, often
Documents that have legal implications,                  unintentionally, but never the less it
such as waste transfer notes, cell burial                happens!
location plans, herbicide records and landfill
exemption certificates, should be retained               It is our recommendation that an Invasive
and recorded. KMP’s enable this to happen.               Weed Hygiene Plan is implemented. This
If for any reason a control programme is                 involves us providing simple documentation
disputed in a Court of Law then it is                    for site use, pictures to help site staff
important to prove due diligence. KMP's                  identify     invasive      weeds       and
record the decision-making processes used                recommendations for fencing off and
to determine a control solution and go a long            protecting invasive weed. We regard this
way to prove that due diligence has been                 as a fundamental part of any Invasive Weed
taken.                                                   Management Plan.
Finally, there is always a residual risk                 The single most important aspect of good
attached to invasive weed control. At PBA                hygiene is to have all known invasive weed
Solutions we look to uncover any potential               stands fenced off. This vastly limits the risk
residual risks and highlight them to our                 of disturbance. Because fences need to be
clients. It would be foolish in the long run to          installed so to allow for root spread, it is
make false promises. KMP's help with the                 beneficial to have a specialist such as PBA
process of understanding the residual risk               Solutions to install or specify fencing to
attached to a control programme.                         ensure it is correctly located to stop
                                                         invasive weed roots from being excavated.
An example of residual risk is that of using
root barriers on the perimeter of a                      Application for landfill tax exemption
development site. In time to come a
service provider may want to install a new               Customs & Excise tax waste that goes to
pipe, which would breach the root barrier                landfill. Currently the rate is £32 (April
allowing invasive weed to re-establish itself.           2008) per tonne increasing year on year.

          For more information call PBA Solutions on 01202 831151, visit:
          For more information call PBA Solutions on 01730 893460, visit:
                                    or email
                                   or email

                                                                               Consultancy Services3/12/08
  Page 3                                       Invasive Weed Consultancy Services

There is a lower rate currently £2.50 tonne (April           As invasive weed roots extend several
2008) applied if the waste contains less than                metres in the soil profile it may be
5% visible invasive weed. In addition, it is                 necessary to excavate to these depths
currently possible to get tax exemption from                 to get sample material.
Customs & Excise in certain circumstances.
Application for exemption requires survey data               Environment Agency application for
and information pertaining to historical land use.           on-site burning
 At PBA Solutions we can collect data and apply
for exemption as part of the invasive weed                   As part of a solutions package, on-site
management process.                                          burning may be implemented. If waste
                                                             is to go off-site to landfill then the
Soil testing for other forms of                              method of burning dead stems is seen
contamination                                                as a form of pre-treatment.              To
                                                             undertake this operation, it is important
It is important to ensure that waste designated              to get permission from the Environment
for landfill is correctly described and not                  Agency and the local council.              If
contaminated with anything else other than                   permission is granted, a procedure for
invasive weed. Contamination testing must be                 burning must be adopted that enables
undertaken to accurately describe the waste. It              burning to be completed in a safe and
is important that no other contaminates are                  organised manner. It is worthy to note
present at levels which would make the                       that even if permission is given, it is still
proposed       waste     "Hazardous    Waste".               possible to be prosecuted for causing a
                                                             public nuisance. Because invasive weed
Only invasive weed contaminated waste can be                 stems generate a thick white smoke, it
buried. The Environment Agency will want                     is suggested that the later point is given
contamination test analysis to verify this and               due consideration.
must be notified 1 week in advance of burial.
                                                             Environment Agency application for
If a residual chemical has been applied to treat             applying herbicides near water
invasive weeds it may be necessary to
understand how persistent it is in the soil. This
is especially important if waste is going off-site           It is important to realise that if chemicals
or is to be buried, at PBA Solutions we can                  are to be applied near water there is a
arrange for this kind of soil testing.                       risk that the chemical may contaminate
                                                             the water body, and potentially kill fish or
At PBA Solutions we can organise soil testing.               endanger humans.
When taking waste to landfill it is important to
understand that testing has to be relative to the            The Environment Agency takes this very
amount of waste that is to be disposed. If large             seriously and requires applications
volumes of soil are to come off-site, then several           (WQM1 notification) to be made if
samples should be taken.                                     herbicide is applied within 5 metres of a
                                                             water body. The definition of a water
It is important that soil sample locations are               body includes: drainage channels,
plotted on a site plan and retained in the                   streams, rivers, ponds, lakes, reservoirs,
Invasive Weed Management Plan. The depth of                  canals and dry ditches. PBA consulting
sample needs to be relative to proposed                      is experienced in completing WQM1
excavation depth to get accurate contamination               applications and can assist clients in
analysis data.                                               making application on their behalf.

           For more information call PBA Solutions on 01202 831151, visit:
                                    or email

                                                                                Consultancy Services3/12/08
 Page 4                                        Invasive Weed Consultancy Services

Viability tests to assess rhizome status                    They also recommend that a Japanese
(Japanese Knotweed)                                         Knotweed Management Plan is in place.
                                                            In fact they are quite forceful in the way
We can test samples of Knotweed rhizome,                    they push this recommendation onto
usually at the end of a treatment programme.                developers.      They state that "it is
The test is undertaken to stimulate re-growth by            essential that you set up some form
putting the sample in an artificial situation that is       of Japanese Management Plan (KMP)".
near to perfect for stimulating re-growth. A                They go on to say that "You need to
viability test helps to substantiate that invasive          identify a clerk of works to oversee the
weed has been suitably controlled.              The         plan". In short, developers are obliged to
Environment agency (EA CoP 2006) states that                seek professional advice.
Knotweed roots can stay dormant for 20 years,
making viability testing an important aspect of a           Method statement for local authority
control programme. Where clients want to                    approval
ensure that they have done everything
reasonable and practical to control Japanese                Planning Departments may request
Knotweed this additional test should be                     method statements for invasive weed
undertaken.                                                 control as part of the planning process.
                                                            At PBA Solutions we have the expertise
At PBA we offer viability tests, either on their            to provide this kind of report and are
own or as part of an invasive weed solutions                always happy to interface with Developer
package.      Viability tests should not be                 and Planning Departments alike, to
regarded as conclusive evidence. The service                ensure that current best practice is
is no more than a scientific experiment and                 implemented from the outset.
subject to a number of factors which could
adversely effect the results. However at PBA                Site Waste Management Plans
we undertake to complete this work
professionally using accepted scientific                    Since April 2008 there has been a legal
protocols.                                                  requirement to complete Site Waste
                                                            Management Plans. This is mandatory
Clerk of Works (watching brief)                             on all development projects over £300K.
                                                            At PBA Solutions we believe that invasive
At PBA Solutions we offer a Knotweed Clerk of               weed control can have a significant
Works Service throughout the UK and have                    impact with on-site waste management.
staff positioned in the Midlands, London and on             We can advise on methods that can be
the South Coast.                                            used to reduce the waste generated from
                                                            invasive weed control. Our innovative
Furthermore, once appointed we can usually                  approach to on-site invasive weed control
get personnel on-site within 48 hours. The                  enables us to utilise Environment Agency
Environment Agency state "We recommend                      current best practice with our unique
that you have a Clerk of Works responsible for              services, to divert invasive weed waste
the management of Japanese Knotweed".                       from landfill.

           For more information call PBA Solutions on 01202 831151, visit:
                                    or email

                                                                               Consultancy Services3/12/08

To top