Hi there. Inspired by another pond blog, I’ve decided to write my own, to share the joys and pitfalls of having a garden wildlife pond.
I live with my wife and little girl in the top left hand corner of Wales [ (c) Oliver Postgate], in a cottage overlooking Anglesey. We live in a wind-swept location in ffridd country – that zone where field systems become patchy and give way to moorland. It’s an exposed location and gets its fair share of wind, as well as snow and ice. Not your typical location for a garden pond then!
Why did I want a pond? Well, I have always loved ponds and pond dipping, and used to regularly drag my parents off to various watery places to look for animals. My mother was a biology teacher and we had a microscope at home, so as well as seeing the standard tadpoles, newts and invertebrates, I got to see some of the smaller stuff – nematode worms, the little ‘freshwater sea anemone’ Hydra, rotifers, protozoans and larger algae such as the beautiful Volvox, which looks a bit like a slowly rotating bright green, partially transparent orange. I’m also a keen gardener and I’m always very frustrated by the relative narrowness of ‘water gardening’. Gardening is such a diverse thing with so many different styles and plants available, yet when it comes to water gardening the approach is very stereotyped, with the ideal seeming to be a cross between one of Monet’s waterlily paintings and a koi carp pond, fringed with large drifts of bog primulas. This is supposed to be created by planting everything in neat little plastic baskets. Now I’ve nothing against water lilies or bog primulas and I’m sure many people get a lot of pleasure from koi (I doubt that plastic baskets really give anyone any pleasure). But is that really all there is?
I wanted to create something using native pond plants. Aha, I hear you cry, nothing original about that, lots of people plant ponds with native plants. Well, up to a point. About ten years ago I started working in nature conservation, and had to learn the various native water plants for my job. The vast majority of these – including many species highly suitable for growing in ponds – are simply not available in cultivation. Most of the native ‘pond plants’ that you can get are not really pond plants at all – they’re marginals that like growing with their feet wet, things like kingcup (Caltha palustris) or ragged robin (Lychnis flos-cuculi). Why are so many native species ignored – are people not aware of them, are they difficult to grow or are we just so set in our ways that we don’t try anything different?
We constructed the pond in 2007. It’s a standard pond liner sort of affair, about 70cm deep in the middle and about 4m x 3m across. The shape is rather uneven partly because I like it that way and partly because the ground is very stony (of which more in a minute). The hole was lined with old carpet, followed by the liner, followed by quite a large quantity of low-nutrient substrate – mainly some old builders sand that was knocking about, some slate waste, and a couple of bags of commercially available aquatic compost to provide the small amounts of nutrients that are needed. With hindsight maybe the slate waste was not such a great idea as it has sharp edges and could puncture the liner. So far I’ve been lucky though. Slate waste does have the advantage that it’s cheap and very readily available in these parts.
Constructing the pond proved a greater challenge than I expected. I had known that the garden soil was stony and shallow from my experience planting shrubs and trees (lets just say that a crowbar is an invaluable garden implement). After digging for a time I hit a large stone, which we only managed to move with the assistance of my Marine brother-in-law.
The following weekend I started digging again and almost immediately hit an even larger boulder, which could only be removed with the assistance of the local farmer and his tractor. We opened up the sheep-proof fence that surrounds the garden, fixed a chain around the boulder and towed it onto the heath.
Since the ground is sloping, I used the spoil and assorted rocks dug from the hole to build up a sort of dam / earth bank that looks quite similar to one or two of the smaller dams on the reservoirs in these parts. If I’m feeling pretentious, I can pretend it’s a homage to a glacial moraine. The result looked pretty bare for a while but now it’s planted up (and to a certain extent been allowed to revert) it looks better. I don’t think it will ever look really natural though. Here’s how it looked in February 2008:
After filling the pond, it went through the usual new pond phases. First the water turned brown as all the sediment from the sand and slate waste became suspended in the water column. This steadily changed to a green soup as microscopic algae grew in the pond and used up the nutrients in the water column. However, this then cleared fairly rapidly as populations of waterfleas and other animals built up to eat the plants. The pond was almost immediately colonised by pond skaters and whirligigs, and soon afterwards by the local palmate newt population and to my consternation, by a great diving beetle. These enormous beetles are ferocious predators capable of eating virtually anything else in a pond smaller than them, and surpassed only in appetite by their larvae, which will also eat animals larger than their own size. If you are wondering how they do this, they inject digestive juices into their prey and then suck up the resulting soup through their jaws. There is a gruesome account in King Solomon’s Ring by Konrad Lorenz of two approximately even-sized diving beetle larvae grabbing and killing each other simultaneously in a deathly embrace.
After some soul-searching (and fishing the diving beetle out once) I decided to let nature take its course. She laid eggs and there were a few larvae around that summer, but they didn’t seem to establish and I haven’t seen an adult or a larva for quite some time. Diving beetles were not the only predators to arrive at the pond relatively rapidly, but that’s for another time.