Monday saw the entire garden team and many of our volunteer gardeners routing through the undergrowth amongst primed stinging nettles and lacerating brambles in the pursuit of Himalayan balsam (Impatiens glandulifera). It has many common names including Indian balsam, jumping jack, policeman's helmet, Indian touch-me-not, ornamental jewel-weed, pink peril and poor man's orchid. This invasive relative of the familiar tender busy Lizzie has become increasingly established along the boundaries of Harlow Carr particularly along the stream which transects the garden. It is a fast growing thug growing to two meters with broad leaves and a high tolerance of shade. It can quickly shade out our native flora and is common throughout Britain particularly along stream and river banks. It is swiftly dealt with by the first frosts but the damage is already done and the prolifically produced seed overwinters readily. The banks of watercourses regularly flood in the winter months but where the soil stabilising native plants have been smothered out the banks are susceptible to erosion. The flowers also produce large amounts of nectar and are popular with many native insects. This may seem like an arguably beneficial attribute but these pollinators are being drawn away from our sometimes less generous native wildflowers which are then unable to set seed.
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