However clever the design of your pond, it is not until it has plants in it and around it, that it really begins to come alive. No matter what the finished project is intended to be – fish pond, water feature or wildlife habitat – the presence of plants adds not only to the aquatic environment itself, but to the overall aesthetic balance of the whole garden. Few other areas in a garden can equal the variety of forms and colours of the array of plants which suit a watery home and the final effect is, in many ways, limited only by your own imagination.
Not all aquatic plants are the same in terms of their requirements and a well planned pond will take this into account, providing the various groups – marginals, floaters, oxygenators and deep-water plants – with suitable places to thrive. The choice is a wide one – from exotic to native and from subtle to spectacular – so there really is something to suit everyone.
Marginals are useful in giving vertical perspective to the pond, drawing the eye upwards from the surface of the water. Naturally occurring around the edges of ponds, these plants are usually accommodated on a purpose-built shelf or ledge around 6-9 inches (15-22cm) deep and are usually planted in pond baskets – perforated pots – to ensure the development of healthy roots. When they are first brought home, they should be positioned so that the top of the pot sits at the water surface level, though once they have become established, they can often be repositioned – the label usually giving the maximum depth they can tolerate.
Typical examples of marginals suitable for most ponds include:
- Brooklime (Veronica beccabunga)
- Bog Bean (Menyanthes trifoliate)
- Corkscrew rush (Juncus effusus spiralis)
- Marsh Marigold – (Caltha palustris )
- Yellow flag- (Iris pseudocorus )
- Water crowfoots – (Ranunculus sp.)
- Water Horsetail – (Equisetum fluviatile)
- Water Mint – (Mentha aquatica)
Final size is an important consideration in the garden pond and most of these will grow to cover an area of around 30-50cm (12-20in) and sometimes more. Although often seen on sale, the likes of the bulrush (Typha sp.) and reeds (Phragmites sp.) are significantly bigger plants and tend to be vigorous and invasive once established, making them best suited to the larger pond.
Floaters and Oxygenators
Many kinds of plants float on the surface of the pond, drawing nutrients directly from the water via roots which are un-anchored in soil. They range from the small native duckweeds (Lemna sp.) which are perhaps 5mm across to the much larger and more exotic Water Hyacinth (Eichornia crassipes). Floating plants offer a simple and instant way to provide additional shade, though many of the commonly sold varieties come from warmer climes and will only survive one season – though they usually spread well enough in the British summer to make the investment worthwhile. The native Water Soldier (Stratiotes aloides) however, will come back year after year.
Oxygenators are an essential element in a healthy pond, helping to oxygenate the water and absorbing excess nutrients which might otherwise fuel algal blooms. Commonly sold – and highly effective – as an oxygenator, Canadian pond weed (Elodea canadensis) is only really suitable for larger ponds, since it is an extraordinarily vigorous and invasive species and will require drastic thinning out if it is not to choke a small water feature. For smaller ponds – or those intended as wildlife habitats, the native curled pondweed (Potamogeton crispus) is a far better bet.
Deep Water Plants
Planted at the bottom of the pond, some 18-60 inches (45-150cm) below the surface, the deep-water plants include probably the most iconic of all water plants – the water lily. When first purchased, the water lily’s basket needs to be stood on a column of bricks so that its leaves lie just below the surface. As the stalks grow, the basket needs to be progressively lowered until it rests on the bottom. Alternatively, you can trim off all the mature leaves and position the plant at the bottom, allowing the new shoots to grow until they reach the surface. The leaves of deep-water plants, along with floaters, provide good surface cover – ideal for wildlife and vital for reducing the problems of algae.
The majority of pond plants are very easy to look after, grow well and require little in the way of maintenance beyond an occasional tidying up to remove dead foliage or over-blown flowers – though it is important to choose plants which suit the pond’s size and depth. With careful selection and a little imaginative planting, the pond should provide an attractive focal point in the garden throughout most of the year.