Indian Balsam

Impatiens Grandiflora

Another Himalayan pest

Considered the worsted invasive weed of all

Brought here by 19th Century gardeners, from various parts of the Himalayan mountains, like so many others of our 'die-hard' invasive weeds.  This one doesn't have deep roots, in fact it is a half hard annual, like it's cousins the Busy Lizzie's, also Impatiens and commonly used as summer bedding plants.  Indian Balsam is fortunately only confined to growing along water courses and on damp ground, however it produces so many seeds, that it soon takes these areas over completely and leaves little or no room at all for the wide variety of native swamp plants, which include a wide variety of Orchids; among many other types of plants, pushed to the edge of extinction, by this monster.  

Indian Balsam often gets to 2 metres in height and it grows just as well under trees as it dose in full sun.

The Environment Agency, here in the UK, consider this plant to be our biggest problem, with regard to invasive weeds.  Simply because of it's ability to spread by seeds and it's ability to re -root, when pulled up, if left in a damp location.  Personally I think it is neck and neck with Rhododendron, but the infamous Japanese Knotweed is considered less of a threat, despite its deep rhizomes, simply because it cannot seed it's self here.

 Exploding Seed Pods

As you can see, from the above picture; there are many big fat seed pods.  The riper they get, the more primed they are to explode.  Just a slight touch of a ripe pod, will cause it to burst open quite violently, casting it's seeds many metres, in all directions.  They occupy most river valleys in the UK, from source to mouth, even up on Dartmoor, they swarm and multiply in the swamps like locusts and they seem to be an unstoppable force, destined to destroy much of our native fauna, and cause a huge reduction in biodiversity, which in turn affects the whole food chain.

Just look at this picture below; a whole swamp, completely taken over by it.  I don't really understand the point in having a nature conservation area, as this is supposed to be; if they just allow plants like this to destroy most of the native plant species.

Control

Any control of this weed, needs to be organised and thorough.  There is little point in removing a bit from one area; because it will simply spread back there again.  It needs to be done one valley at a time, from source to mouth and up every tributary and in every garden, where it resides.

Pulling it up and then taking all the tons of material some where dry, but that would cost a fortune, even in just a small area like here in the Exe Valley; this plant is everywhere.

I have removed bits up on Dartmoor, but it's an up hill struggle, really; I need lots more help.  But great in roads have been made towards the eradication of Rhododendron and Japanese Knotweed, the Environment Agency is aware of the problem, so hopefully it will just be a matter of time before this menace of our waterways is gone forever.