May 6, 2007
Pond Life…The Good, the Bad and the Ugly
By CHARLIE DIMMOCK
WHEN I worked in a water garden centre, customers were forever asking me: 'I've got this creature in my pond what is it?' Well, lots of things live in ponds, I had to tell them.
I've found many weird and wonderful creatures in ponds over the years, including believe it or not an eel. They can travel quite a long way over land between one stretch of water and another.
In one customer's pond, I came across a couple of stone loaches, which are river fish, so how they got there I've no idea. These days I'm more often asked about all the creepy-crawlies not just what they are but what they do.
Snails tend to be the things people notice most. They think they are necessary because they eat decomposing vegetation which they do but they also eat live water plants.
So, if you make a new pond, don't buy snails straightaway.
Get your water plants established and, after a year or two, when everything has settled down, then you can introduce some snails.
Go for the ramshorn varieties, which have flat, coiled shells they are the least voracious.
Should surplus snails be removed?
Usually not. If you've got fish, they'll eat a lot of the snail eggs and the smaller snails while they are still softish-shelled.
However, if your plants look eaten to bits and aren't establishing well, then, yes, by all means pare down the snail population. You'll often find them clustering on one plant to which they are partial usually the water hawthorn.
Freshwater shrimps are something else pond owners worry about. They look like woodlice with long shrimptype feelers at the front and can grow up to an inch long. They are quite good for the pond since they scavenge on the bottom and filter the water. They'll also attract birds, which eat them.
There are several kinds of beetle you might see on the water on fine summery days. Water boatmen are slim and have one long, thin leg sticking out each side of the body, like oars, which they use for scooting themselves over the surface.
They feed on dead and dying insects that drop on to the surface of the water. You can attract them by taking a blade of grass and just touching the surface of the water it makes a tiny ripple and the water boatmen come towards it to see if there's something to eat.
The diving beetle is another one you might see. They are dark and ovalish with beige legs and hang out mostly in waterweeds but you'll sometimes see them come to the surface then dive down again.
They get a bad Press because they are said to eat fish but it's only the fry and tadpoles they go for, and if something didn't keep the numbers down, your pond would be heaving.
Then there are all your different dragonflies and damselflies. The adults are the spectacular stage but, like butterflies, they don't live long. The larvae are big and ugly with bug eyes like underwater aliens and they eat all sorts of small pond creatures including tadpoles.
Some of them take three years to reach maturity and you don't usually see them because they stay hidden in the waterweeds. Often all you'll notice are the empty cases left on iris stems when they've hatched out.
But one water insect that's very welcome is the daphnia, or water flea.
These sometimes turn up all on their own in summer they look like clouds of tiny, translucent dots moving in short, quick jerks in clear, shallow water near oxygenating waterweeds.
You get them only if the pond is mature and the natural balance is just right. So, if you see them, you know you've got a healthy pond.
You can buy live daphnia at fish centres, where they are sold partly as fish food and to clear the water, which they do by filtering it.
Water bugs won't bite but some people are squeamish about them.
We had a few customers like that at the water garden centre, who called me in to get rid of them. My boss used to love that because all the big old plants we'd remove in the process made free propagating material for our sales area.
The clearout's due now unless you want a swamp
SPLIT up overgrown marginal plants in spring if you let them get too big, they'll swamp the pond and you'll have to clear everything out and start from scratch. Most can be lifted out and divided in late April or early May but do the water irises a few weeks after they've finished flowering, in late June, so you don't miss out on this year's blooms.
Do it just like dividing herbaceous border plants split them up with a spade, save the strongest-looking crowns to replant back into your planting basket and discard the weaker ones. Use pond compost or garden soil free from any chemicals or fertiliser and put an inch of gravel over the surface to stop the soil washing out when you lower the basket back into the pond.
Don't divide waterlilies until they desperately need it and then do it around mid-May. If you buy a small variety in the first place, you'll hardly ever have to divide it. Don't divide waterlilies up too small, thinking: If I just put a tiny bit back, I won't have to do it again for a long time. It's better to put three good bits back in one basket so you quickly have a proper covering of leaves again, which is better for the biological balance of your pond.
And when you replant your new crowns, take off all the bashed or broken ones because they'll just rot and foul the water.
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