Himalayan Balsam | Life in the English Cotswolds

Turn and run! Nothing can stop them. Around every river and canal their power is growing.
Stamp them out! We must destroy them. They infiltrate each city with their thick dark warning odour*.

Plant hunters have over the centuries introduced many beautiful plants to our gardens but they have also brought in others that have, as they escaped from its confines, become troublesome weeds. Japanese Knotweed, Fallopia japonica, creates problems by damaging river banks and pushing up through concrete, even entering houses; Himalayan Balsam, Impatiens glandulifera, is pretty enough with their hooked pink and white flowers but smothers native plants. Both are difficult and costly to eradicate. But the one that can cause the most trouble – and is undoubtedly the most impressive – is Giant Hogweed.

Long ago in the Russian hills, a Victorian explorer found the regal hogweed by a marsh … he came home to London and made a present of the hogweed to the Royal Gardens at Kew*.

Giant Hogweed, Heracleum mantegazzianum, was introduced to Britain from the Caucasus in Victorian times and soon became a popular addition to parks and gardens for, although similar in appearance to our native Hogweed, Heracleum sphondylium, these were giants in every way. Huge flower heads above equally large leaves reaching way into the sky – up to twenty feet or more in exceptional specimens – were something to marvel at. A hardy perennial, the plants shot up over the course of just one summer adding to its popularity, although it can be a few years before the plant flowers after which it dies. With up to 100,000 seeds from each plant, it soon multiplied and before long had found its way back to the marshy land adjacent to rivers and canals as in its homeland.

I wonder how long it took the Victorian gardeners to discover the problems associated with the plant for it not only spreads rapidly, it also is extremely toxic. Covered in sharp bristles that scratch the skin it is the sap from the plant that can cause major injury. Skin contact with the sap when exposed to sunlight results in severe dermatitis: itching and redness develop into blisters and dark wheals. These can last for several years. Contact with the eyes is even more dangerous for permanent blindness can follow.

So what do you do if you find Giant Hogweed in your garden apart from turn and run? It can be treated with weed killer and the ideal time to do this is when the plants have a large leaf area but before they flower. It is essential not to handle the plant at any time – even when it is dead – for every part of it including its roots will injure you. If you are tempted to carry out control yourself (and it may be wiser to call in a specialist eradication company (please, not me!)) then you must wear a complete coverall and full face and eye protection. You also need to remember that the clothing will also be contaminated and should be destroyed.

Fortunately, Giant Hogweed is rarely encountered in gardens. You are more likely to find it growing in waste places in the wild and it may be wise to report its presence to your local environmental agency. Attitudes toward it vary from country to country for this is not just a British pest – it is found in many other temperate regions of the world including the USA and Canada.

Perhaps at this point, I should remind you all that the majority of garden plants are harmless enough and that gardening and plants give a huge amount of pleasure. Happy gardening!

* The Return of the Giant Hogweed: lyrics by Genesis, 1971

The lower reaches of the river Otter turn from fresh water to brackish as the river joins the sea. At low tide, mud and salt flats are exposed creating a safe habitat for the hundreds of seabirds and waders that feed, breed or rest on migration there. This area, including its wildlife, I have written about earlier – it can be found by clicking here.

This post describes a walk a little further upstream where the river flows through fertile fields of wheat and where cattle and sheep graze in lush riverside meadows.

The river – which like our river in the secret valley – is really little more than a stream (or ‘brook’ as we say where I originate from – English dialect is another fascinating subject that I might write about one day!). One moment fast flowing, the next slow, but always crystal clear, the view is one of steep banks and stony bottom. It is here, in the shallower water, that the trout – huge in comparison with our tiny ones at home – sway in the current, waiting for food to be swept down towards them and their ever open mouths. At one place where the river runs across a steeply shelved weir, a salmon run has been built: a series of steps for the salmon to leap to reach the upper levels of the river for spawning after their long migration. Whether they still do, I do not know, for salmon stocks in England are dwindling fast.

Wood and water, just nothing but water and wood, for the crowds of visitors that explore the river close to the beach and form long queues at the ice cream stalls have all been left far behind. Now the sights, sounds and smells are only those of nature on this glorious late summer’s day. The trees are only just beginning to show a hint of the autumn to come but, somehow, their berries have already stamped their mark on the autumn landscape, glowing in and reflecting the sun’s warmth.

Along the river bank, swamping much of the native flora, the Himalayan Balsam is giving a final explosion of colour before the first frosts destroy them for another year. And explosion is the correct description of their bursting seed heads which throw the seed far and wide as they split open. Found in many damp places throughout the country, for its seeds are also dispersed by the movement of the water, the Himalyan Balsam is an unwelcome immigrant to Britain which is virtually impossible to control. A member of the Impatien family, its seedheads are similar to those of our familiar garden Busy Lizzie.

Along the final stretch of our walk, the river is backed by the same red sandstone cliffs that can be seen by the coast. How many millenia did it take for this gentle stream to cut its way through to its present level? My photography skills – or perhaps my patience – did not allow me to get shots of the kingfishers that darted up and down as a flash of azure along this reach of the river. High up in the rock face, their nesting holes (or were they the breeding sites of the sand martins that had already begun their long flight south to winter in Africa?) were more easily photographed.

The ten mile walk to the source of the Otter will have to wait for another visit to the West Country. Oh, and I nearly forgot to mention, otters can be found – but rarely seen – along the whole length of the river.