Himalayan balsam

Pretty, isn’t it? And it looks lovely when it lines the route of a railway line or a river. But…

In the Himalayas, from whence it hoves, balsam is kept reasonably under control by rust fungus (Puccinia komarovii var. glanduliferae for those who want to be technical). But in the UK the rust fungus is only a recent arrival while the balsam was brought by those Victorian plant hunters so is already very well established. The rust fungus is doing a reasonable job although it has now been discovered that not all populations of Himalayan balsam are destroyed by PC var. glanduliferae so new strains are now needed to infect the resistant populations.

So what is the problem with the balsam?

The issue is that although it is only an annual it grows very fast and very tall (5-6 feet/nearly 2 metres) and has a lot of big leaves.

This means that it takes the light from all but the most vigorous plants that try to cohabit with it. While this is not actually that much of an issue on the heath where it is mainly doing battle with nettles and brambles who are well able to hold their own, on railway banks and river banks it crowds out most of the native plants that would naturally grow there.

And even this would not matter that much – although it definitely would not be desirable – except that the balsam also has incredibly short, shallow roots – unbelievably short and shallow when you look at the height of the plant and the size of the leaves. These are two uprooted plants and you can see by matching them to the toe of my boot, how tiny a root system they have.

And the issue with this is that when they die down in the autumn, having crowded out all of the other longer rooted plants, there is nothing to hold the soil together on steep railways or river banks. Not a great idea at any time but especially if there are heavy rains.

On the heath this is not too much of  problem but the rangers, and especially Rory, the wildlife and invasive species expert, are anxious to keep the balsam under control – by sending out us volunteers to search and destroy. We were working over on the west of the heath by the Ice House today – a wild area rarely visited by the public – mainly because it is such a forest of nettles and brambles, quite apart from the balsam, that it feels closer to the Brazilan jungle than Hampstead Heath.

The balsam tends to hide in plain sight – initially hard to spot until you get your eye in when you discover great clumps of it nestled amongst the tallest nettles and prickliest brambles! However, once found, thanks to its tiny root system it is very easy to pull out. But how to dispose of it? Definitely not dropping it on the ground where it will merely put down new roots and get going all over again, nor by dropping in the compost where it will do the same thing.

The trick is to break the stems and hang them out to dry. The stems are large, hollow, translucent and filled with water.

If you snap them in half or even in three you cut off their life source – and then you ‘hang them up’ in a tree so that they dry out and die.

This was a particularly juicy specimen that fellow voluteer David and Rory had just pulled up. But elsewhere we were doing them in bundles and just shoving them in any bit of tree we could find – laundry day in the forest!

The main thing is to get to them before they flower and go to seed as each plant can produce up to 800 seeds which are shot into the air as the seed pods ripen and can land up to 7 metres away. The seeds can also remain viable for up to two years in water which means that when they grow along river banks the seeds can get washed for miles down the rivers.  Bees are also alarmingly good at spreading the pollen as the balsam produces lots of nectar.

Anyhow, we had a satisfyingly successful day’s balsam pulling although since the day was hot and we were all wearing Tshirts, I think we all came home with a good crop of nettle stings up our arms to show for our efforts. Thinking of which….

Rory told us that he had heard that dock leaves actually were not that good for counteracting nettle sting. Because are quite rough they may help pull any stinging nettle hairs out of your skin but they don’t help the sting – whereas crushed plantain leaves work much better. So when I got home I asked Google who sent me to Wild Food UK:

Ribwort Plantain seems to be a very versatile addition to the medicine cabinet being an antihistamine, antifungal, antioxidant, analgesic and even a mild antibiotic. Used as an antihistamine, Ribwort Plantain is very effective at dealing with nettle stings or insect bites/stings unlike Dock which is just a placebo but if your children get stung and you can’t find any Plantain, placebos work.
The leaves can also be used to make a tea that acts as an effective cough medicine.
The roots apparantly make an effective treatment for rattlesnake bites!