Over-Wintering Pond Plants
Over-wintering pond plants is easier than you think, but it’s more about tidying up to please the eye than anything else, as after all, most of the time there is no manual intervention needed on the autumn maintenance of naturally growing water plant habitats. In nature, all areas of deciduous fauna die back naturally and this decomposition breaks down and adds its own nutrients to the following year’s growth. However, there are a few golden rules to follow when tidying up your water garden.
Marginal Plants, Bog Garden Plants and Moisture Loving Perennials
2.) If a plant is growing in the water such as – Rushes, Iris or Aquatic Grasses, I would recommend that you cut them back to about 10-20cm above the water level, however, never cut back below the water level as some species and their cultivars can literally drown from the water that is being drained down from their stems and collecting in their tubers. A good example of this is Lotus plants. You should never cut back Lotus plants below the water surface as this will definitely result in the death of these beautiful plants.
3.) I also recommend that you refrain from feeding pond plants after July as they need a few months, to absorb any artificially added nutrients before they prepare for winter dormancy.
The Leave Well Alone List
Never cut back any of the following plants in the Autumn, as they are either evergreen and need no intervention at this time, or that they simply will not appreciate being cut back until their new re-growth appears in the spring.
Iris Louisiana (all)
Water Lilies, Nuphar Species and Deep Water Plants
This category of plants are the least fussy of them all which means that you can cut them back as low as you want or, simply leave them to decompose which will add nutrients and healthy silt to the bottom of your pond.
Apart from the frost hardy Hydrocharis (Frogbit) and Stratites Aloides (Water Soldiers), (by the way, water soldiers are actually a deep water plant and not strictly free- floating) all other free floating plants excluding the nuisance plants like pond lovers nightmare (Duckweed), are tropical and therefore, must be over-wintered in a heated greenhouse, conservatory or on a window sill in your home. These plants include Pistia Stratiotes (Water Lettuce), Eichornia Crassiopes (Water Hyacinths) and Salvinia Natans. My advice is simply just to float them in a cat-tray or similar water holding container in about 4-10cm of water and they will stay happy.
Do not put them back out in your pond until May or even June if you are in a exposed area that suffers late frosts.
The above paragraph only applies if you live in the Northern Hemisphere and doesn’t apply if you live in a warmer, tropical or sub-tropical area.
Now my last piece of advice to you is, to sit back, relax, and wait for spring!