Himalayan Balsam
Himalayan Balsam is now widely established in other parts of the British Isles becoming an invasive species weed. The aggressive seed dispersal, coupled with high nectar production which attracts pollinators, often allows the Himalayan Balsam to out-compete native plants.
Himalayan Balsam is often found on riverbanks, growing up to 2 metres in height.
Each plant lasts for one year and dies at the end of the growing season.
Himalayan Balsam:
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has dark green, lance-shaped leaves with jagged edges
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has reddish coloured stems
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flowers from June to October
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has large, brightly coloured flowers that are usually in variable shades from purple to pale pink
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can produce around 2,500 seeds per plant each year
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has explosive seed pods that can throw seeds over 6 metres away from the plant making it an extremely invasive plant
Giant Hogweed
A robust, bristly plant that has a coarse foliage and almost flat-topped flower heads with larger petals round the edges. These broad flower heads attract many insects, especially the orange or brownish Soldier Beetle. You should take great care when identifying giant hogweed. Contact with the plant, particularly the sap, can lead to severe blistering and scarring. Giant hogweed closely resembles native cow parsley or hogweed. It can take four years to reach its full height of 3-5 metres and flower.
Giant hogweed:
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has a reddish-purple stem with fine spines that make it appear furry – like a stinging nettle
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has hollow stems
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has spotted leaf stalks
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has leaves up to 1.5 metres wide
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flowers in June and July
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has flower heads that are usually 50 centimetres wide – each flower head can produce 50,000 seeds every year
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has seeds that can stay in the soil for several years before they develop
Other invasive weed species we specialise in at Helmrig Ltd
Australian Swamp Stonecrop
Also known as the crassula plant, this Australian species destroys pond life by spreading like a sponge over the water surface.
Parrot's Feather
Spreads very easily and has become an invasive species and a weed in many areas.
Floating Pennywort
Forms dense rafts and outcompetes native plant species. Reduced light levels below the rafts can cause die off, waterweeds and algae and reduce water oxygenation levels.
Common Ragwort and Buddleia
The daisy-like, yellow flower heads of Common ragwort may be pretty enough to the casual observer, but they belie the poisonous nature of this plant. Renowned as a weed of paddocks and pastures, where it can be harmful to livestock, it is not usually such an issue in gardens or on waste ground. In fact, it is the food plant of the black-and-red Cinnabar moth: sometimes its black-and yellow-barred caterpillars cover the plant, totally stripping the leaves. Common Ragwort is a biennial, flowering in its second year from June to November. Common ragwort is a relatively tall-growing plant that has clusters of yellow, flattened flower heads, and leaves that look ‘feathery’ because they are very divided.
Buddleia is a popular garden plant that was introduced into the UK from China in the 1890s and has now become widely naturalised on waste ground, along railway cuttings and in urban areas. Its familiar purple flowers bloom from June to October and attract all kinds of butterflies and moths looking for nectar sources. Its winged seeds are dispersed by the wind and find it easy to colonise stony ground. Buddleia is a very familiar bush, with large, drooping spikes of densely clustered, small, purple (or sometimes white) flowers. It has long, narrow leaves and the flowers have a honey-like fragrance.
