thompson     Thompson Village sign

A Breckland Village

 

Thompson's Country File

Himalayan Balsam - contribution from Pam Spacey

Himalayan Balsam

What a pretty plant!  Beware, it has a secret plan to take over our river banks and areas of damp ground. 

 A native of Western Himalaya, this annual was first introduced to Britain in 1839.  Since then it has naturalised along riverbanks and ditches, showing its preference for moist soil, although it will grow anywhere. 

Himalayan balsam is a relative on the busy Lizzie and is known by a wide variety of common names, including Indian balsam, jumping jack and policeman's helmet.  It is a tall, (3metres) robust, annual producing clusters of deep pink helmet-shaped flowers.  The seed pods that follow open explosively when ripe, shooting seeds up to 7 metres away.  Each plant can produce up to 800 seeds.

So what's the problem?  Himalyayan Balsam tolerates low light levels and, in turn, tends to shade out other vegetation, impoverishing habitats.  In winter when it dies back, it leaves large bare areas along riverbanks and ditches which are sensitive to erosion. 

What is the solution?  It has shallow roots and can be easily pulled up before it sets seed.  Recommended practice for management for cultivated plants is to cut to ground level by the end of June and before the plant flowers.

Here in Thompson, the plant can be seen around College Road, particularly along the watercourse.  If you are interested in controlling this plant and protecting our ditches, then contact Pam on 483711 or email us

More information on Himalayan Balsam can be found on the following sites:

http://www.rhs.org.uk/Advice/profiles0705/himalayanbalsam.asp

http://www.dgsgardening.btinternet.co.uk/himalbals.htm

Thanks to Down Garden Services for allowing us to use their image.

 

Conker Trees - contributed by Jimmy Johnson

 

For the past three or four years one of our favourite trees has been turning brown in the middle of the summer.  

Ugly brown and black marks appear on the leaves which eventually die and fall. Rather than being the beautiful trees with which we have grown up, by late June the Horse Chestnuts in our woodlands and hedgerows bear the scars of the activities of a new pest.  

If an affected leaf is held up to a bright light, small dark elongated shadows can be seen moving in the leaf: these are the grubs of a leaf miner moth.  Lift one of the scabs with a pin and the grubs can be seen clearly with the aid of a magnifying glass.  I’ve counted a maximum of 100 on one hand of leaves.  The grubs eat away the centre of the leaf between the upper and lower surfaces which causes it to die and eventually fall.  The grubs then form a pupae and either turn into an adult moth within a few weeks or can survive the winter.

The grubs are the larvae of a leaf miner moth discovered in northern Greece in the early nineteen eighties and officially recognised as a new  species in 1985.    Since then the moth has spread across virtually all of Europe including the UK.  There are no known natural predators although this year I’ve seen some Blue Tits attacking the brown scabs on the leaves in order to eat the grubs.

What can we do?

Unfortunately, very little!

There is no evidence that even heavy infestations kill the trees although there is some that the tree may be weakened and the combination of “Bleeding Canker” and the moth’s larvae will lead to its demise.  

Sweeping up and burning the dead leaves which contain the pupae when they fall and especially during the autumn, will help to reduce the numbers of adult moths but we have to recognise that these trees are so common in our landscape that such actions will only be scratching at the surface of the problem.

Longer term, there are some varieties of horse chestnuts from other countries which are more resistant to attacks from the moth could be planted to replace the European variety, but I’m not sure whether these produce proper and prize winning conquers.

For those who would like further information some of the following links may be of interest:

http://www.forestry.gov.uk/fr/INFD-68JJRC

http://www.forestry.gov.uk/website/forestresearch.nsf/ByUnique/INFD-6YUB8B

http://www.forestry.gov.uk/website/forestresearch.nsf/ByUnique/INFD-6YSKJF

http://ukmoths.org.uk/show.php?bf=366a