Country diary: The irises have taken over the pond, and only leeches are left | Claire Stares

Langstone, Hampshire: The pond is almost devoid of life, apart from several of these greenish-grey segmented worms burrowed into the silt at the bottomMy wildlife pond has been leaking and, after several unsuccessful attempts at patching it up, the race was on to replace the liner before the smooth newts return to breed. Twenty-five years ago, I planted a single yellow flag iris (Iris pseudacorus) in the shallows. While it is a British native, it's an invasive species and has taken over my modest two-metre-diameter pond, sprawling out of its planting basket, self-seeding into the silt. The thick mat of fleshy rhizomes - some as thick as my wrist - has smothered the more delicate plants such as miniature bulrushes, water mint and water forget-me-not, and displaced much of the water, leaving the pond almost devoid of life.After hacking through the irises and baling out the water, I hadn't found a single dragonfly or damselfly larvae, pond snail or water beetle. The only remaining residents were horse leeches (Haemopis sanguisuga), and plenty of them. Several of these greenish-grey segmented worms had burrowed into the silt at the bottom, while others were hidden in the folds of the liner. While the majority of leeches inhabit fresh water, horse leeches are only semi-aquatic, and more were lurking beneath the pebbles on the pondside beach. Continue reading...