Small balsam and Enchanter's nightshade battling for supremacy in the understory of the Wilderness
Two of the common understory species in the Wilderness are the native Circaea lutetiana (the Enchanter’s nightshade – dark green leaves) and the invasive alien Impatiens parviflora (Small Balsam – light green leaves). Enchanter’s nightshade is a widespread woodland understory species but in the Wilderness it is being displaced by the earlier growing and larger ‘Small’ balsam which is native to Central and Eastern Asia. Small balsam was introduced to the UK in 1823 and now occurs throughout Britain.
Small balsam is taking over our woodland floor at Foxcombe hall and has spread to the Pilkington trust woodland. This species has an astonishing level of phenotypic plasticity as it can flower and set seed even if a tiny stunted plant in deep shade and dry soil or grow taller than stinging nettles.
Wood sage seems to be OK but enchanters nightshade and even dogs mercury are vulnerable to being shaded out As far as I tell small flies pollinate the flowers.