Pond strife
IS IN NEED OF SOME TLC, THIS IS THE PERFECT SOMETHING ABOUT IT
IF YOUR POND IS LOOKING OVERGROWN, STRAGGLY AROUND THE EDGES OR
TIME OF YEAR TO DO
BY THE end of the season, most ponds are looking a bit overgrown and in need of a sort-out. And if you keep fish, a few basic precautions will keep them safe and happy through the winter.
Cut back
Trim moisture-loving perennials or bog plants growing in the area around the pond. A few species are late flowering, so take care not to cut down plants with more flowers to come.
The spring and summer-flowering kinds, however, can be cut off completely – foliage and all – roughly 2in above ground level.
Next, work on marginal plants growing in shallow water at the edge of the pond. Dead-head any that still have flowers to come, but cut down all those that have finished for the year – their foliage will be looking very tatty by now.
If evergreen waterside plants, such as some sedges (Carex) still look good, or dwarf bulrushes have seed heads, then leave those for winter decoration – just remove any broken stems or damaged foliage to tidy up their appearance.
Pull out yellow leaves of water lilies. This prevents rotting vegetation falling back into the pond and fouling the water (any leaves that are still green and healthy can be left alone). Water hawthorn often flowers quite late into autumn, so if it’s still looking good, leave it alone till later.
Thin out
Now is not the time to divide water plants (wait until spring), but if you have some that you want to get rid of, it’s a good time to lift them out, complete with the planting basket they grow in. Tip them on to the compost heap, where they’ll soon rot.
De-sludge
Over several years, garden ponds slowly start to fill themselves in, since plants and wildlife generate waste that sinks to the bottom as silt.
By the time a pond has been established for five years or more, some of this sludge needs to be removed to keep the water at the correct depth. This helps to maintain a suitable temperature for fish, aquatic wildlife and the beneficial bacteria that keep conditions in check.
De-sludging is best done in autumn. There’s no need to empty the pond of plants and fish, or even siphon the water out. Just take a square plastic pot, 4-6in across, to use as an underwater scoop.
Lean over the water and work carefully across the floor of the pond, between plants, gathering sludge. Lift out gently, allow to drain for a few seconds and then bale into a bucket.
Work slowly, so as not to stir up the murk too much. Don’t try to get all the silt out. Plants need some to root into and it houses lots of beneficial bacteria, so aim to leave a layer a couple of inches deep all over the floor of the pond.
Protect
Place a large clean plant pot or 12in length of plastic pipe on its side in the deepest part where it’s well surrounded by water weeds, so fish can take shelter in case of herons or other predators.
Cover the surface of the pond with a net, stretching it taut so the centre doesn’t droop into the water. This will help deter herons, but the main purpose is to collect falling leaves before they drop in the pond and rot.
This is because they use up valuable oxygen when they decompose, as well as helping silt build up.
Remove the leaves from the net regularly before their weight drags them down into the water.