Sunday, 19 July 2015

Dora's Field, Rydal. Invasive Control Work.

A concerted effort has recently been made to rid Dora's Field, named after Wordsworth's daughter, of non native invasive plants, namely Japanese Knotweed and Himalayan Balsam. 

Countryside Rangers from St. Catherine's and High Close with help from volunteers and a work experience student combined forces to deal with this problem.  

Japanese Knotweed has spread alarmingly quickly... indeed have stands of Himalayan Balsam in Dora's Field.
Bees, bumblebees in particular, are highly attracted to Himalayan Balsam because it provides a rich source of pollen and nectar especially in late Summer.

Native plants are often overlooked by the bees in favour of Himalayan Balsam. More Himalayan Balsam gets pollinated at the expense of Native plants. No wonder it has become so prevalent!
A beekeeper told me recently that Himalayan Balsam is akin to fast food for a bee.... "But too much of the same food can be just as bad for  bees as for people!" He pointed out.

By getting rid of Himalayan Balsam, Native plants, which are great providers of pollen and nectar, will be able to flourish instead.  There are much better alternatives to Himalayan Balsam for bees such as...
...Touch-Me-Not Balsam seen here in the foreground or Foxgloves; many more Native plants could also thrive and help the bees maintain a 'balanced diet' at the same time! ..... How about Ragged Robin, Knapweed, Yarrow, Betony, (see image below) White Clover, Red Deadnettle and Purple Loosestrife for starters?
Bumblebee "tucking into" Betony flower on parkland at St. Catherine's.

As an aside Purple Loosestrife (Lythrum salicaria) is highly invasive, and a massive problem in the United States...just as Knotweed and Himalayan Balsam are here... Away from its natural environment it has run riot, significantly degrading and creating havoc with the ecosystem of the North American wetlands. 

It was introduced by early colonists from Europe to plant in their gardens in the New  World...It is a horribly familiar story the World over.  
Work experience student, Luke with arms full of Himalayan Balsam heading for the fire site.
Academy Ranger, Pete with volunteer, Sue dragging down a bulk bag full of Himalayan Balsam. Laura is in the background dealing with the Knotweed.
Volunteer Coordinator, Greg, who volunteers to do this role, is about to bag up some knotweed ready to be burnt on site.
The cut stems of Knotweed are now ready for...
... an application of  Glyphosphate; it travels down the hollow stems to the rhizomes (sprouting root system) with devastating results. It is a time consuming process but highly effective in eradicating this pernicious weed.

Cutting back the stems will also help to exhaust the rhizomes but it may take several seasons to accomplish this!
Burning up!
There was time to strim the path...
...and 'tidy up' with the leaf blower.

To sum up, a difficult task was made manageable through good team work.


  1. Good work team. Wow, applying the glyphosphate that way must be very time consuming, I hope you didn't have to do too many! Still, it's a good tip for the domestic gardener too I'd have thought.

  2. Thank you. Your comment is greatly appreciated. Hopefully a good start has been made; however Knotweed is so incredibly persistent it may well require work over the course of several years to be certain it is gone for good!

  3. An image of a bumblebee and a Himalayan balsam flower from this post appeared on images of bees and Himalayan balsam elsewhere on the internet. I read your post and I ask where the evidence is that Himalayan balsam is a problem for Native plants. Elsewhere conservationists claim that biodiversity is destroyed and riverbanks are left bare and unprotected when Himalayan balsam dies back. Again, is there any evidence for this?

    1. Thanks for your comments. There is strong empirical evidence that Himalayan Balsam is able to suppress native species and contribute to river bank erosion. A large stand of Himalayan Balsam used to dominate an area below St. Catherine's; only a few native Touch Me Not Balsam plants were able to grow under these conditions. After years of eradication work the situation has reversed. The vast majority of Balsam plants here are now Touch Me Not; so from my own observations Himalayan Balsam, if left unimpeded, is a problem for native plants.
      Many internet sites express concern. I think the Inland Waterways Association puts it well...."Himalayan Balsam grows in dense stands crowding out native plants. It can take over whole areas of river and canal bank over spring and summer before dying back in the winter. When Himalayan Balsam dies back it leaves banks that it previously dominated bare having crowded out native species. With no roots left to strengthen the bank, the bank becomes more susceptible to erosion". I hope this answers your questions. Alternatively, South Cumbria Rivers Trust or Eden Rivers Trust web sites may be of interest.