Water wonderful world
With Diarmuid Gavin A pond adds another dimension to your garden... but get the balance of plants right E for maintaining a healthy pond
ver since Charlie Dimmock performed her magic on the nation’s gardens, ordinary people like you and me have succumbed to the temptation of a water feature.
Its attributes are obvious – beautiful, natural, reflective, gentle sounds, a hint of nature and a haven for wildlife.
However, unless they are done well, water features and especially ponds can become a mess. Understanding what you want to achieve and making the right decisions for your project is very important.
I’ve learnt this to my cost. For the past five years I’ve had an unfinished project – three ponds, meant to be linked together with waterfalls, two of which leak. It’s my promise to myself this spring to get them in order.
I made a bad choice by being convinced to go with a polypropylene construct which is very difficult to weld together and it’s proving almost impossible to find where the leaks are springing from.
I’m going to remedy this by using black butyl liner, which in my experience is the best way to go.
After sound construction, a good combination of planting is key for a healthy pond.
Oxygenators are necessary to keep the water clean as they suck the nutrients from the water which otherwise encourages a blanket of green algae.
Hornwort and the water buttercup are a good choice here, but avoid Elodea – Canadian pondweed – as this is extremely invasive. Floaters are just placed on the surface of the water and provide some additional surface cover and food for fish.
Duckweed ( Lemna) and Fairy Moss ( Azolla) tend to take over very quickly and carpet the pool.
Choose instead native plants, such as frog bit ( Hydrocharis), which has pretty white flowers in summer, and water soldiers ( Stratiotes) with spiky foliage.
Don’t worry that these plants disappear in winter – they sink to the bottom of the pond to overwinter and will re- emerge.
Waterlilies or nymphaeas are the most desirable of aquatic plants. Their large and fragrant blooms are second to none and their leaves provide superb cover for fish.
They will only flourish in still water so don’t consider them if you have moving water, such as waterfalls, fountains or pumps. Plant in their baskets in a sunny spot in May or June and lift and re- pot after four years. Dwarf varieties are perfect for mini ponds or half barrels as these can be grown in shallow waters.
If your lily pond has become overgrown and the plants are congested, you will need to lift and divide them as you would perennial plants.
Choose hardy varieties as the tropical varieties won’t survive our winters. Marginals naturally grow in the shallow edges of ponds so these are appropriate if you have a pond which slopes gradually or the pond has a shelf at the side which is around half a foot deep or so.
While they aren’t necessary for healthy pond life, they play a role in softening the edges of a pond, creating a naturalistic effect.
There are plenty of suitable plants, such as yellow iris ( Iris pseudacorus), the flowering rush ( Butomus umbellatus) and pontderia, the pickerel weed, which has cylindrical spikes of blue flowers.
For drama you can’t beat the white arum lily, Zantedeschia.
Finally, a note of caution. Any amount of water in a garden that children have access to can be dangerous, so think very carefully before you introduce it.
It may well be that it has to be fenced off for a couple of years or that it simply isn’t appropriate. And while your own children may be welleducated about the hazards, a visiting child might not be – and it only takes a couple of minutes for something terrible to happen.