Grow Greener with Garthdee Field Allotments Association

Tag: pests Page 1 of 2

Himalayan Balsam (again)

Pat at the council has been in touch with this bad news.

Dear Allotment Tenant

I am sorry to inform you that Himalayan Balsam seed may be present in the compost delivered to the allotment sites listed below.

A number of allotment tenants have advised us that they have identified seedlings growing on the compost as being Himalayan Balsam.

The compost has now been removed from all the allotment sites except King Street where the compost is being managed on site.
(For King Street Allotment tenants please do not use this compost until advised it is Himalayan Balsam free which will be when there is no new growth of annual seedlings.)

Greyhope Road
Holburn Street
Garthdee Field
King Street
Sclattie Quarry
Gray Street

If you have used any of this compost or are an allotment tenant on one of the above sites, please be vigilant as Himalayan Balsam spreads very easily and is an non-native invasive weed.
Unfortunately, this plant is spreading everywhere especially along our river banks. You may have seen Himalayan Balsam when walking along the banks of the River Dee or the River Don. It flowers predominantly in July and August and is particularly prevalent either side of the Brig o Dee, the Persley Bridge , the Diamond Bridge, along Seaton Park and at Donmouth.

Himalayan Balsam is an annual plant and produces colourful flowers. After flowering it produces seeds for the following year and when touched the seed pod bursts and sends the seeds flying in all directions.

It is important that this plant is controlled and not allowed to produce seeds that will be next year’s plant. Perhaps the best control is to pull the plant out of the ground before the flowers are fully out and left to dry, wither and die as per the average weed. It can be hoed out or cut down too. Control requires to be carried out before the flowers are fully out which is usually just before August. The plant will be recognisable to most during June and July.
If pulled out before the flowering stage which is before the seeds are produced it can be composted. If you are unsure of the stage it would be best not to compost and just leave the pulled plants to dry and wither.

Please find attached an information sheet on Himalayan Balsam.

Further information and advice is available online using the links below or searching “Himalayan Balsam”

Kind regards


Himalayan Balsam

Plotters will be aware of this message sent out by Stuart 10 days ago.

Pat Wilson at Aberdeen City Council has emailed to say that some recipients, at other Council allotments, of the recent delivery of compost from the Council have discovered Himalayan Balsam growing in it. This is a non-native invasive species.
“This is an annual plant which grows each year from the previous year’s seeds, so the aim of control is to prevent the plant from flowering and setting seed. Scattered plants are best pulled by hand, being careful to remove the whole plant. Cutting or grazing on dense stands can also achieve control but cutting should not be attempted once the seed heads have formed, as this would effectively spread the plant.”

The young seedlings look like this:

Himalayan Balsam Seedlings

If you have helped yourself to compost please keep checking for these seedlings and pull them out but don’t put them in your compost bin. It has been suggested to leave them on the surface to let them dry out in a controlled environment then bag and removed them from the site for disposal.

Over the next few months we will all have to keep checking as the seeds work their way to the surface. Hopefully with a combined effort we will be able to get rid of this invasion. If we can prevent these plants from reaching the flowering stage we should be ok.

Stuart has arranged for the Council to come and remove the remaining pile of infected compost.

This is a website with information on Himalayan Balsam.

A New Year Resolution

It’s time to declare war on New Zealand flatworms – total war. For me, they have replaced slugs as public enemy number one. Slugs only attack some of the crops we grow. NZ flatworms threaten to annihilate our earthworms.  They are also as ugly as sin and ooze evil from every pore.  There can only be one plotters’ response – EXTERMINATE!

Bruce on flatworm patrol

Why so now? I suggest two reasons. Firstly, a recent Conversation Newsletter Article (link coming up below) spelt out the importance of earthworms for healthy soil and plants, and the environment generally: and we all know the threat NZ flatworms pose to our earthworms.  In summary, the article says earthworms are:

  • brilliant organic matter recyclers and wormcasts contain key nutrients
  •  tireless engineers improving soil structure and condition
  • good indicators of soil health and toxicity levels
  • a food source for many species, so adding to biodiversity
  • expert restorers of damaged or neglected soils.

Earthworms are the good guys and our friend’s enemies are our enemies.

Secondly, research shows that some modern practices and tendencies in plot management seem to favour the NZ flatworm.  For example, I have started to use plastic membranes and carpet as weed inhibitors and winter soil protectors and these are known to encourage flatworms.

It seems unlikely that we will ever be able to completely defeat and remove our flatworms.  Recent Aberdeen University research reports (links below) show that flatworms are present on 70% of our plots and 90% of Slopefield’s plots are infested. However, there are lots of actions we can take to reduce flatworm numbers.  This may tip the balance back in favour of our earthworms.

Actions against NZ flatworms include:

  • removing clutter and flatworm refuges from our plots.  These are flat stones, plastic, wood, carpet and fabric
  • set up flatworm traps using the above and check them on a regular basis
  • kill trapped flatworms with lemon juice or drowning in salt water in secure containers
  • add organic matter to encourage earthworms
  • use grass paths to support earthworms
  • exercise strict bio-security to avoid spreading flatworms to new areas

When our plots were surveyed by researchers they found that flatworm refuges were found on many plots. Eighteen plots had a small number of refuges; 14 plots more than a small number; 14 had many refuges and only 1 was refuge-free.  The number of flatworms found increased with the number of refuges and carpet was found to be the worst source of flatworms, followed by plastic, fabric, stones and wood in that order.

So what is to be done?  In the first instance, I am going to stop using carpet to suppress weeds. I am going to do a big Spring tidy up, removing clutter. I am going to set my flatworm traps and check them regularly. I already keep a lemon squeezy on site.  I should also replace my central slab path (built up over many years as free slabs became available) with a grass one, but this is a big job and a sore one.

Know your enemy

So, I hope this can be a big focus for us over the year ahead.  If you want to read more about the NZ flatworm threat and responses these links will help:

Conversation Newsletter Article

GFAA Advice Notes

Report on GFAA Flatworm Study

Our New Zealand Flatworm Problem

We have just received the interim report from OPAL and the University of Aberdeen on our flatworm problem.  It does not make for great reading as it suggests that over 70% of our plots are infested with these pests.

Suggestions as to how to deal with flatworms, taken from this very helpful report, has been incorporated into a new page under the Advice and Support tab above.  You will also find a copy of the interim report.

New Zealand Flatworm Survey

The University of Aberdeen are conducting a survey of NZ Flatworms and are looking for a number of allotment holders to participate, both those with and without NZ Flatworms and would appreciate answers to the following questions

1. Do you have New Zealand Flatworm on your plot at present?
2. Have you had New Zealand Flatworm on you plot historically?
3. Would you be happy for someone from Aberdeen University to visit your plot and record presence and abundance of NZ Flatworm, soil pH, take a small soil sample and record earthworm numbers?
In addition they would ideally like to talk to you or alternatively get you to fill in a questionnaire to enable them to gauge the scale of the problem and find out more about your experience of NZ Flatworm. This would be done mid-March- April at a time convenient to you.

4. If you are not able to participate in the study they would really appreciate it if you could fill in this short survey Hard copies of the survey can be obtained by contacting Annie Robinson direct at

If you wish to participate please contact Annie as soon as possible. It would be helpful if you would be good enough to let me know if you decide to participate.


New Zealand Flat Worm Study

Thanks go to Bruce Taylor for alerting me to this study.

Aberdeen University has announced it has researchers taking part in a national survey of the New Zealand Flatworm‘s spread and its effects on our gardens, plots and fields.

2015-06-12 at 08.59

As we know the Flatworms kill our native earthworms, but the university site contains some truly gruesome details about how they go about their murdersome business and how difficult they are to eradicate once they get established. It appears that the flatworms can reduce to 10%  of their body weight for up to a year as they await another earthworm dinner.  Perhaps the weight-loss industry ought to be sponsoring this survey!

More details, including how you can participate, are available via these links:

Aberdeen University Research Press Release

National Flatworm Research Project

Unwelcome Visitors to Garthdee Field

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