This invasive plant has not been found in Brickfields Park to date as we have no upstream water flows with Himalayan Balsam in them. This species description is provided to aid others in identifying the plant.

Pictures © 2005, , FBCP

Himalayan Balsam - Impatiens glandulifera
Also known as
Policeman's helmet, Pink peril, Poor Man's Orchid, Indian Balsam, Indian Touch-Me-Not, Ornamental Jewelweed

An annual highly invasive weed native to the Himalayan region of Asia, hence its name. It is the latest in a range of imported plants that find the climatic conditions in the Uk very favourable, and without natural predators is rapidly becoming a nationwide problem. It is partially shade tolerant and favours riparian and damp areas particularly riverbanks, ditches, wetlands and streams which serve to rapidly spread the plants seeds, form which new plants grow each year. Introduced to British gardens from the Himalayas in 1839 (some reports cite it initially escaped from the gardens at Kew where it had been introduced as a greenhouse plant).

Growing to between 0.5 - 2m (1.6 - 6.5ft) with an open upright habit. Hollow much branched bamboo like stems tinged purple, with dark green glossy lance-shaped serrated leaves on short stalks which continue into the leaf to form a strong central rib. The leaves are arranged in pairs, or three to a node and about 18 - 16cm (3 - 6in) long. Loose clusters of pink, purple or white orchid like flowers 30 - 40mm long, appear July - October, on a long single stem arising from the same stem node as the leaves forming whorles. The flowers produce copious amounts of nectar and form a large chamber particularly inviting to bees who are one of the plants main pollinators. It is very aromatic such that large stands of Himalayan Balsam can become overpowering to the senses. Himalayan balsam has a poor root structure so it is relatively easy to pull by hand, cut stems will re-grow from the roots. Flowers mature to a large dark brown 5 segmented seed pod that explosively bursts when ripe ensuring a wide distribution area for the seeds, which can number up to 2500 for each plant. The seeds 2 - 3mm (0.08 - 0.12in) in diameter are also capable of germinating underwater. Another charming local name, "bee-bums" has arisen as it is just the back end of a bee that can be seen when it visits a flower of this plant, it has also recently become known as the "Pink Peril" in conservation circles.

Himalayan Balsam can be controlled by hand pulling, mechanical cutting or by grazing. Either way the main aim in controlling this weed is to prevent it setting seed, so any work should be completed before the plant has time to set seed, which for the Uk can be late June onwards. Control may need to extend over two or possibly three years due to the long viability time of the seeds. Where waterways are concerned an "upstream strategy" is recommended so that re-colonisation is minimised. Removal of the plant should be to an approved disposal site, being aware that moving it could help to distribute the plant to new sites. Composting is not an appropriate means of disposal as the seeds can survive the composting process. More difficult, but more effective is to composing burn the plant on site. So far there are no known "safe" biological agents however it can be killed by Glyphosate, but this requires early application and specialist knowledge, and extreme care where rivers and waterways are concerned. In the UK, some local wildlife organisations organise "balsam bashing" events to help control this particularly invasive plant.

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