Making a Wildlife Pond

I’ve previously written about the pond we acquired when we moved house. It started life as a very deep, formal pond for Koi carp, but we’ve been transforming it into a home for wildlife. The liner had to be replaced, as I think it was leaking (and I wanted to re-shape the pond and reduce the depth too).

Late January – the liner is in place, with a layer of underlay over the top, and the pond is ready to be filled.

To protect the liner, I put the old underlay into the hole, and then a layer of new underlay over it. Next was the liner itself, followed by another layer of underlay over that. I know this sounds strange – it’s called underlay, not overlay after all; the clue’s in the name – but the idea is to protect the liner from being damaged by anything sharp that might be put on top, such as plant pots, bricks and slabs for raising up water lilies, and any stones or sharp objects that might be in the soil you put in for marginal plants.

I wanted to get it right, so I followed instructions in a book called ‘The Water Gardener’ by Anthony Archer-Wills, apparently a very respected figure in the industry. The book isn’t always entirely clear on the details, and I’m not convinced about some of the construction methods – more on that later. This is the pond the next day, when snow and cold weather stopped play…

You can see I built a shelf for planting all the way around the perimeter, and bricks along the edge of the shelf to stop the earth collapsing. In the deep section there are two slabs, supported on bricks, for a water lily and a water hyacinth.

The start of February – the shelf has soil on it, and has been planted up, and the pond is nearly full

By the middle of March, the frogs had moved back in, and had started laying frog spawn…

I think I got the pond filled just in time. Last year I think most of the tadpoles were eaten by the fish, but they’ve been relocated elsewhere, so the tadpoles should have less predators this year. Panning out, this is what the pond looked like at that time. You can see we’ve planted the far side with some dogwoods: Cornus sanguinea ‘Midwinter Fire (times 1) and Cornus alba ‘Sibirica’ (times 2). It needs more, but I’ll take some cuttings this year, and try to be patient

The water got cloudier and cloudier, and a scum of green algae formed on the surface – it didn’t look very appetising. Something had to be done. Rather than spending a fortune on bags and bags of aquatic compost, I had just used garden soil on the pond shelf – which is, I believe, as the book directed. I wondered though – could all the nutrients in the soil mean that the pond would inevitably remain scummy?

I remembered reading that putting bunches of lavender in a pond will clear the water. Obviously, at that time, there was no lavender to be had. So instead, I tried rosemary. I couldn’t imagine it would work. But, amazingly, it did – after only a week, the water had cleared, and the algae had disappeared. Surprisingly, the water has got clearer and clearer. So much so, you can see right down to the bottom. And the tadpoles have now hatched….

The water may be clear, but there is a bit of a problem with the level – it’s going steadily down. I’ve been emptying a water butt into it now and then, but that’s not enough. I think the problem is that the water is wicking out and over the sides via the layer of underlay over the top. The book did say you might need to have a system to top up the water, but it’s just losing too much. Mains water isn’t great for topping up a wildlife pond (and the supply is too far away anyway). There’s only so much rainwater you can collect. I’ve already got three water butts, but the water in those will be needed for watering plants when the prolonged dry spells arrive. Here is the edge, with the underlay lapping over and tucked into the soil around the pond…

To stop the water loss, I’ve cut away the under (over?) lay so that the liner, which of course isn’t absorbent, is exposed. The next problem is how to hide the liner. I’ll have to top up the soil on the ledges. Hopefully the plants should hide most of it once they’ve grown up. I may just need to put some stones around the edge too…

Don’t let anyone say I don’t fill this blog with pretty pictures! To the left (front) side of the pond the liner dips down and extends under the width of the bed to create a bog garden for plants that like damp soil (Ligularia, Rodgersia, Hostas, Iris sibirica, etc.). I’ve left the under (over!) lay on that side because I want the water to over-flow into that bed when there’s been a lot of rain. I’ve also run a pipe from the down-pipe on the side of the workshop where there isn’t room for a water butt. So the rain that lands on that face of the roof feeds straight into the pond. Hopefully that will fix the problem with the water levels. This is how the pond was looking a few days ago…

The water hyacinth is flowering nicely. You can see the water level still needs to come up somewhat. Hopefully that will happen in time. We’ve planted up the bed on the left of the pond with damp-loving perennials (from Claire Austin, as well as Ligularia seedlings and Iris divisions that we brought with us from our previous garden). They’re not showing much as yet – hopefully they will put on some growth over the summer. We’ve got tadpoles, water beetles and water boatmen. It might take a few years, but I can’t wait until there are dragon flies and damsel flies skimming back and forth over the surface all summer long…

Text & images © Graham Wright 2021

Draining the Swamp…

Well, the pond, actually; but hopefully I got your attention! I’ve turned what was once a koi pond, with clear water (provided by some very elaborate filtering equipment) full of colourful fish, and with a rather twee wooden bridge crossing over it, into something horrible.

But as the saying goes, you can’t make a souffle without breaking wind. No, that’s not it… Omelette! – I meant omelette. The fish were taken away before we moved in last year. I stopped using the pumps because I’d seen newts in the pond, and read they can be drawn into pump impellers and killed. The water turned cloudy, only slightly ameliorated by first, barley straw, and then lavender clippings.

The pond pumping equipment – looks complicated. If anyone wants it, let me know!
This is the end that goes in the water

You might wonder why I’m bothering to empty the pond. Well, firstly, I suspect it’s leaking, because the level never stays up; there’s always a few inches of the liner showing, which isn’t attractive. Secondly, the shape isn’t ideal. It’s 90cm deep, which seems excessive to me, and the figure of eight doesn’t look right for a wildlife pond (which is what I’m aiming for). And I want to put in different levels for different plants, ideally with the ledges filled with soil to plant directly into, rather than resting plant pots on.

The newts are all out of the water for the winter now (I’ve encountered quite a few while working in the garden – a sharp eye and a great deal of care is required to avoid casualties). Which is good, because it meant I was able to use the pump to get the water out. My attempts at syphoning the water had failed miserably. Apparently you need the end of the hose to be lower than where you’re syphoning from, which wasn’t possible in this case. Using a bucket would have been back-breaking work and taken forever.

The pump got most of the water out, but I’m having to scoop out the rest with a bucket, which isn’t easy. I put a garden fork through the bottom, but the water isn’t draining out. There are lots of frogs hiding in the thin layer of silt on the bottom – as I come across them I’m transferring them to the temporary pond I set up…

I made the temporary pond 60cm deep, because it turned out there were fish in the pond after all – some must have escaped the net; presumably they were much smaller then. They’re shy creatures, spending most of their time near the bottom, but I’d counted four of them on the odd occasion when they rose to the surface, and that’s how many there turned out to be. Only one has orange colouring, the rest are plain, and I’m wondering if, rather than Koi, they’re actually just river fish – though I’ve no idea how they came to be in the pond (maybe they’re flying fish!) Perhaps, like many plant varieties, Koi carp don’t breed true from seed.

I won’t be putting them back in the main pond when it’s ready because, as I’ve said already, it’s going to be a wildlife pond, and the fish will eat the wildlife. I’ll either have to make a separate pond for them somewhere, or find another home for them. Fish and chips, anyone? (only joking).

I’ve started taking apart the waterfall behind the pond…

While the fibreglass waterfall sections looked quite realistic – almost like real stone – they’re not really my style. I’m intending to level ‘the hill’ and plant some dogwoods (Cornus) species in it’s place, to make a backdrop to the pond. With their coloured stems they should look very impressive in the winter. So far, I’ve got one Cornus alba ‘sibirica variegata’ which is a cutting from a cutting, from a cutting, which has bright red stems in winter; and one Cornus sanguinea ‘Midwinter Fire’, which came as part of an order from the excellent Burncoose nurseries earlier this year. I put it into a larger pot to grow it on ready for planting out (hopefully) this autumn. I’ve not grown Midwinter Fire before, but even in a pot, sat on earth in the middle of a garden construction site, it looks wonderful…

Actually, the photograph doesn’t do it justice. The gradient from orange through to red makes it glow as if it’s on fire. This effect can be achieved with other shrubs… but only by setting them on fire!

I found the remains of the wasp nest under the waterfall; beginning to decay, with just a few, sleepy wasps left alive…

I’ve levelled the area to the right of the pond, between the pond and the wooden workshop building, and begun to plant it up. The main feature is an Acer griseum (Paperbark maple), a seedling from the garden of one of my customers. This is a small tree, often grown multi-stemmed, and renowned for its bronze-coloured peeling bark. In the autumn the leaves turn all sorts of shades of red, orange and yellow – quite spectacular. To the right of it is another shrub from the Burncoose order; Hydrangea paniculata ‘Limelight’; also potted on to build it up ready for planting. It’s filled with beautiful white flower clusters in mid-summer, which fade gracefully to the dried, brown heads that will stay on the plant all winter (they’re great for cut flower displays).

You can see the path that will meander around the back of the pond, made from re-claimed materials – edged with bricks on end, and filled with compacted rubble. A layer of slate chippings will finish it off (if it doesn’t finish me off first!)

So, as you can see, I’ve been busy. But there’s a lot to do yet. I’m continuing to dig out the honey fungus rhizomorphs that have spread throughout the garden. Opportunities to work in the garden are reducing as there are less and less daylight hours, and it gets colder and wetter. A few trees and shrubs are still holding on to their leaves – one of our pear trees, for instance – but most are now bare. I always find this a difficult time, and this year it seems worse than before. But even now there are signs of better times. Spring-flowering bulbs are just beginning to poke their snouts out of the soil, and I’ve noticed that the roses I planted just a few weeks ago are coming into bud. Buds are swelling on many of the trees, too – fat, juicy flower buds in the case of the magnolia, and rhododendrons in particular. It’ll soon be spring. We just need to get through what the poet Ian Mcmillan refers to as ‘the long dark corridor of winter’…

text & images © graham wright 2020