Creatures from the black lagoon

last year's blooms: Above, water iris, with Rodgersia and Achillea mollis in the background
last year's blooms: Above, water iris, with Rodgersia and Achillea mollis in the background
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WITHOUT doubt, the most vile job of the year is clearing out the pond.

Please don’t think for a minute it’s like your Tory MP and his moat, or even Monty Don in his waders.

My pond is a bit pathetic, but I love it all the same.

It was built by the previous owner, out of solid concrete (no butyl pond liners in the 1960s for him).

Unfortunately, he obviously wasn’t a fan of aquatic plants, as it’s far too shallow – barely a foot deep.

No water lilies or fish then, but there is a thriving water iris and marginals. They’ve got to be tough as old boots, as it freezes solid in winter and heats up far too fast in the summer.

If you’re digging your own pond, or buying a ready-made liner, the general rule is 2ft deep. However, mine ticks over quite nicely, but does need topping up in the summer in hot spells, through evaporation.

Some ponds are never cleaned and manage quite nicely, but mine does suffer from leaf fall from the beech hedge.

It would be normal to clean it out in autumn, when most of the leaves fall, but beech keeps its dead leaves on all winter, only losing them when new ones unfurl in spring.

At this time of year, you can remove winter debris.

I use a net specifically for removing duckweed, tiny aquatic plants which float on the surface. They’re especially good at clinging around the iris rhizomes, so if you can’t get the net in, blast the base of the iris with a hose on the jet setting.

When they’re in the main body of the pond, you can scoop them up.

The biggest problem in my pond is Elodea, or Canadian pondweed.

This species is vital for oxygenating the water, but it runs rampant.

As I was too busy doing other things last year, I didn’t thin it out.

By last month, it had filled the whole pond and was breaking the surface. Oxygenators are needed to prevent algal growth (the green slimy stuff).

Once you’ve cleared out all the oxygenators, leave them in a pile by the side of the pond, so any wildlife can get back into the water.

Break off some bits of Elodea and put it back into the pond – you still need some in there.

There’s a chance that with such a sudden change in the natural balance of the pond, the water clarity will drop and will turn green.

If this happens, barley straw tied in a net bag and suspended in the pool will cure the problem (get it at garden centres). This may take a week to several weeks to work depending on the water temperature.

If you want to plant new aquatics, now’s the time to do so.

Then sit back and relax – another foul job done!