How to choose Pond Plants.
A carefully crafted and skilfully constructed hard landscaping project such as a garden pond, whether formal or informal in design, no matter how pleasing the aesthetics of that design, does not truly come alive until furnished with a variety of Pond plants. The addition of plants adds new form and texture and vibrant splashes of colour, changing with the seasons to provide a living, kaleidoscopic canvas set to rival one painted upon by any of the great masters. Quite simply, a garden pond can accommodate perhaps the most diverse array of plants than any other area in the garden and not to appreciate this is to miss out on a great opportunity. Some pond plants also provide vital functions necessary for maintaining the health of the pond environment. A pond, properly constructed, should have different areas to accommodate the many varied requirements of plants that will live in it. Pond plants are categorised relative to the areas of the pond they inhabit or functions they may perform. These categories are Marginal, Deep water, Oxygenators and surface floaters. A sub category is Deep Marginals. Bog plants may also play a part in the landscape scheme surrounding the pond.

Marginal Plants.
Marginal plants, as the name suggests inhabit the pond margins on a shelf area that is between 6” to 9” (15 to 22.5cm) deep and wide enough to be proportional with the overall pond surface area. These plants are moisture loving but may die back if planted too deeply. They are usually supplied in ventilated pots called Pond Baskets ready to place directly onto the shelf or in solid pots ready to be transplanted into a pond basket of your choice. It is important that Marginals are in these ventilated baskets so that adequate water and oxygen flow ensure a healthy root system. Alternatively these plants can be transplanted directly into a gravel bed if the Marginal shelf is constructed in such a fashion as to be able to contain a sufficient depth of gravel. Marginal plants should always be initially planted so that the surface of the pot is roughly at the water surface level. Some, when more mature can be re-located to a lower position and the maximum water level above the pot is usually indicated on the plant label. Marginal plants provide some perspective above the level of the pond and a large number of varieties are available from rambling low cover such as gold Buttons (Cotula) and Brooklime (Veronica Beccabunga) to the proud, sword like upright leaves of water Iris such as Golden Flag (Iris Pseudocorus). A classic tall Marginal is the unmistakeable Bullrush (Typha sp.). Some Marginals are equally at home in both aquatic and terrestrial areas and by planting these together in both areas, a seamless interface can be achieved making it impossible to tell where the pond ends and the surrounding garden begins. Houttuynia varieties and Creeping Jenny are examples of these. Plants can also be chosen for their beautiful flowers in every conceivable colour or dramatic foliage such as that of the Corkscrew Rush (Juncus Effusus Spiralis) or the zebra rush (Scirpus Zebrinus). Themed planting is also popular, for example choosing only indigenous species such as the delightfully named Menyanthes Trifoliata, (Common name “Bog Bean” doesn’t quite trip off the tongue so well!) used extensively in Medieval times for its medicinal properties or the cotton tuft plumed Cotton Grass (Eriophorum Angustifolium).

When planting marginals arrange so that the taller plants are central to the most usual viewing angle with the other plants graduating in decreasing size to either side. Do not plant so as to obstruct views of other parts of the pond unless creating channel like windows to increase the perspective of depth of view. Spreading habit or low growing plants can also be planted in front of taller ones to create denser arrangements with greater dimension. Just like choosing bedding plants it is possible to choose varieties that are early and late flowering to create interest spanning the seasons. Planting density should be three to four marginals for every square metre (10.5 sq ft) of pond surface area.

Deep Water Plants.
Deep-water plants live on the bottom of the pond from depths of 18” to 60” (45 to 150cm) and include perhaps one of the most loved of all pond plants, the delightful Water Lily. Planted in a similar fashion to Marginals in ventilated baskets or specially constructed gravel beds approximately 10” deep (25cm), these plants will grow to the surface where they will provide, together with floating plants, essential surface cover. About 50 varieties of Water Lily are commonly available. Choose a variety that has a leaf size proportional to the surface area of the pond for best effect. Lily leaf sizes vary enormously from the fifty pence piece size leaf of the yellow flowered Pygmaea Rubra to the colossal and also yellow flowered Nymphaea “Colonel Welch” which can be planted to a depth of 5’ (150cm) making it an ideal choice for the larger pond or lake. Lilies will continue to spread year after year (Although they die back completely during Winter) so do not over plant, a pond of surface area 9’ x 5’ (2.7 x 1.5m) will accommodate two medium sized lilies. Lilies are Sun worshipers and although they will nearly always produce plenty of the almost circular Lily pads, they will not produce an abundance of blooms unless the pond is in a sunny position. Another popular deep water plant is the Water Hawthorn (Aponogeton Distachyios) which can be planted to a depth of 4’ (120cm) but is happier at depths of 2’ to 3’ (60 to 90cm) in our climate. A southern hemisphere plant by origin it will provide leaf cover in the winter months and dies back for a period in the summer. A mature specimen will grow a mass of white flowers held proudly just above the water surface amongst a host of lanceolate leaves. In South Africa the flowers are used as salad garnish and are in fact edible (Although it would probably not be a good idea to consume any grown in the average UK garden pond!).

Deep Marginal Plants.
Deep Marginal plants are those that can be planted to a depth below that of the average Marginal shelf (6” to 9” – 15 to 22.5cm) but would not survive at the greater depths that accommodate most of the plants in the category above. Nymphoides Peltata (Water Fringe), Orontium Aquaticum (Golden Club) and Hottonia Palustris (Water Violet) are all good examples that can be planted to a depth of 18” to 20” (45 to 50cm). These are useful as an additional deep water plant in the shallower pond or for planting in an intermediate shelf in the deeper pond. Water Fringe will provide surface cover very quickly and Water Violet, apart from producing the most exquisite fringed foliage both above and below the water plus delicately tinged pale violet flowers, is a good oxygenator. The Gold tipped white flower spikes of Golden Club burst from the water surface like a firework display and this is a plant that is often overlooked, as new plants do not look particularly impressive when displayed for sale.

Oxygenating Plants.
Oxygenating plants are the soldiers of the ornamental garden pond, marshalling the environment into a healthy and stable condition. Oxygenating plants are vital in the battle to maintain a balanced ecosystem using up excess Phosphates and Nitrates so removing the excess food source that could be utilised by un-desirable algae’s.