Garden pond plants & koi ponds | Plants for cover and shade
I am soon going to increase the size of my pond and up until now I have had plants in it. I know Koi purists would not advocate plants in a Koi pond but the Koi in my pond seem to enjoy the cover they offer and I don't want to alter their environment too much so as not to frighten them. What is your view on pond plants and is there anything else I can add to my pond to provide my Koi with cover?
Answwer
I'm afraid I'm a bit of a Heathen like you too. Where there is water I like to see plants and Im sure the fish do as well. Unfortunately Koi seem to appreciate them more for their nutritional or plaything value rather than their cover potential appeal. I have found on most occasions that plants need their own segregated area in which to flourish and if it is pool cover you are after then there are a few plants that will fit the bill of providing pool cover whilst their roots are tucked away safely.
Most lilies will fit the bill if you can provide the depth of water, but if the plants are in a shallow trough like marginal area you might try Nymphoides peltata often known a Villarsia or water fringe lily. This is quite vigorous but easy to keep in check, it has small lily like pads with a small funnel shaped yellow flower, quickly covering a fairly large area whilst other plants are finding their feet. If you have 10cm of water then the water hawthorn, Aponogeton distachyos is worth a try. This is a deepwater plant that is quite happy in moderate shallows.
For proper marginal style plants, the Bog bean, Menyanthes trifoliate can also work in the shallow and provide a fair amount of safe and controllable cover over a pool. The pickeral weed, Pontedaria cordata, fits this bill too and is quite bit taller and flowering blue in late summer. Mimulus guttatus and M. luteus, Sagittaria, Sauraurus and Houttynia are also safe to try, although avoid the latter in a competitive trough situation.