Saturday, 21 October 2017

Pond Plants You'd Rather Not Have

A damp and dark day in Shropshire and though the threatened worst excesses of the unfortunately named, ‘Storm Brian’, have yet to strike us, it’s still raining heavily enough to prevent me working outside.
I had been working in my pond, pulling out the Australian Swamp Stonecrop ( Crassula helmsii) which came from who knows where to set up home with us a couple of years ago, and liked the situation so much it now needs two sessions a year of me pulling it out to keep it under control.
The only weed the pond is supposed to be home to is Curly Waterweed (Lagarosiphon major), which we put in as an oxygenator when we first made the pond twenty or so years ago and which, being less thuggish by nature than its neighbour, continues to float about on the surface of the water in clumps about the same size as those we introduced.
Australian Swamp Stonecrop was introduced to Britain from Tasmania in 1911, was first sold as an oxygenating plant in 1927, by Perry’s Hardy Plant Farm in Enfield, and was first recorded as growing in the wild in a pond at Greenstead Farm in Essex in 1956.
The plant first appeared in our pond as a small light green tussock which had attached itself to the surface of a pot with a plant in it growing just above the waterline and then grew out rapidly to form a dense mass of vegetation. Bits of that vegetation then broke away from the parent plant when I tried to remove it and rooted into other plants in the pond. That is how it has continued to spread around the pond.
Australian Swamp Stonecrop eliminates native flora by out-competing with it. It is shade tolerant, frost tolerant, desiccation tolerant and has no dormant season. The only ways of controlling it at all seem to be to cover small patches of it with black plastic or carpet, or spraying it with formulations of Glyphosate specific to aquatic environments.
In the garden, on a bank above the pond, perhaps, look out for the deep rose pink flowers, spreading habit and vigorous growth of Erica carnea  ‘December Red’, the Winter Heath, adding brightness to our lives in the depths of winter

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