Autumn Care of Pond Plants
October and November are the best months to tidy up your pond or water-garden and, to put your plants to sleep for the winter. If the last few UK winters are anything to go by, a little attention won’t go a-miss.
One of the most important things to give your plants over the winter period is, a rest from growth. I suggest that you stop feeding them and let them go dormant, as they won’t need any nutrients whilst the daylight hours become shorter and the temperature drops. Another important factor is to remove any excess leaves that may have fallen into your pond such as, pine-cones and pine- leaves, apples, berries and any other evergreen leaves, as all these will decompose and cause the water to go stagnant which, could potentially kill off all of the plant life in your pond which in turn, will release toxins into the water which will then kill your fish. If in doubt, do a water test and if you do discover any evidence that there is too much decomposition in the water, my advise is to clean out your pond thoroughly and then do a retest.
Autumn can be spectacular, but in a small garden pond, plants can become rather unsightly. Always cut back untidy marginal plants above the water-line, as the stems will then be able to carry oxygen back into the rhizomes and crowns. Below, I have compiled a list of some marginal plants that certainly will not appreciate any intervention during the winter period as they are evergreen.
My advice also for the winter months is, if you have any Lobelia Cardinalis and or any of the varieties of Iris Ensata in your pond, that you remove them as although both varieties are happy with their feet in water during the growing season, they do prefer to be treated as an outside perennial pot plant during the winter months.
All Water-Lilies and most plants with floating leaves can be safely cut back, although there are a few exceptions. Apponogeton Distachyos is best left alone as it flowers throughout the winter, and although it will get chopped down by frosts and ice, it will soon replenish itself within days, even in mid-winter.
Further advice this winter is to discard any annual floating pond plants such as, Eichornia (Water-Hyacinths) and Pistia (Water-Lettuce), as these will not survive the winter and will have to be replaced. Lastly and if possible, my advice is to move all your deep marginal plants to a slightly lower depth to prevent their roots from getting frozen in a long cold spell. Lowering deep marginal plants by about 6 inches is quite sufficient and your deep marginals will certainly appreciate it.