Autumn/Fall Pond Care & Maintenance
As fall progresses it is a good time to get your pond in shape for winter and prepare for next spring. Water plants grow quickly and, if your pond is generously planted, annual thinning is almost certainly essential.
My pond is probably over planted, but that results in clear water through summer and plenty of wildlife. I also love waterlilies, so probably planted a couple more that would be ideal at the outset.
During summer dragonfly and damsel fly larvae are emerging, along with a host of other water dwelling fauna. So early fall is as good a time as any for a clean-up, although I will still pile up anything I remove around I the edge of the pond and leave it for a day or two to let wildlife escape and return to the water.
Thinning water plants in a large pool is not easy, especially vigorous lilies growing in the deepest part of the pool. You won't get them out with a net or a pair of pond gloves: you either don a pair of waders or you prepare to get wet.
I usually wait for a nice day and put on my swimming trunks, but I admit that's not everyone's ideal. Although I initially planted my waterlilies in planting crates or aquatic planting bags they soon escaped and sent chunky rhizomes with fleshy white roots to roam around the pool. When these get overcrowded some of the rhizomes find their way to the surface, rising out of the pond like curious reptiles.
At the surface they tend to float and bring the rest of the plant with them. You need to cut out some of the plant and remove it before anchoring the rhizome to be kept back to the bottom of the pond.
I find that you have to cut out the old section of rhizome with a knife or pruners. Then I tie the piece I'm keeping onto a brick wrapped in butyl liner using plastic flexible tie. This is usually sufficient to weight it to sink to the bottom of the pond.
It also makes it easier to remove fallen tree leaves with a net: there will soon be plenty of them. I would also cut back irises and other marginal plants that are starting to die back. Their leaves will soon collapse into the water and become harder to retrieve.
Rampant marginals such as bog bean Menyanthes trifoliata, and the common yellow iris, Iris pseudacorus never stay where you plant them. They tend to seed and spread around the pond, particularly if you have a shallow, stony beach area which I have.
Now is the time to thin them out which will mean just ripping out some of the growth to get their presence down to manageable proportions.
Water soldiers, Stratiotes aloides, are floating plants that sink to the bottom of the pond in fall and rise again to the surface in spring, sticking their prickly cactus-like leaves above the surface.
They produce offsets, a bit like strawberries, so there are more of them every year! I remove about half of them in fall and thin them during the year, otherwise they choke everything else.
They help to reduce the sunlight filtering down through the water so they reduce algal growth, in other words green blanket weed.
I would also take this opportunity to thin out oxygenating plants and remove any blanket weed that you can. Areas of the pond that are thick with weed will be the first port of call for spawning amphibians in early spring.
If you decide to leave doing it you may miss your chance.
Once the debris has been left for a day or two for any creatures to make their escape you can compost it. This can come in handy at this time of the year when those first leaves are starting to fall.
Having some really soggy green waste to compost with them gets the composting process off to a great start.