Stocking a Pond
Many of the plants available commercially for garden ponds will be suitable, but, for a more natural look, much better strategy is to introduce a majority of native species—the sort of things that grow in real ponds in your district. However, the law places certain restraints on the uprooting of wild plants, even common ones. Be sure that you have the necessary permission before going to your local pond for supplies; take only a few plants of the kinds you need and cause as little damage as possible while doing so. Choose only places where these plants are abundant. In many ways, it is often better to scrounge what you want from neighbors or friends with established ponds. Hornwort is an excellent oxygenating plant. Some other useful species you can introduce include water mint, waterforgetmenot, water planting, marsh marigold, marestail,yellow flag iris, bog bean, purple loosestrife, frog bit(floating), amphibious bistort (floating) and (at the deepest parts) water lilies. Reed grass (Palmaris) will grow well around the wet edges, as will bog arum, primulas and various ferns. Reed mace will form big, attractive stands and may need some control as your pond matures; unless you have a lot of room or are prepared to carry out continuous management it is probably not good idea to introduce the highly invasive and fast-spreading common reed (phraginites).
There is a good chance that the common toad (and perhaps newts) will colonize unaided—but here, too, you can ask a friend or neighbor for spawn or tadpoles from a well-established pond. A supply of the spawn of the common frog could be even more valuable. This has become a scarce animal in many districts, and founding anew, protected colony could be an important local conservation project_ Remember that both frogs and toads require easy access into and out of the pond—gently sloping banks or strategically placed stones will help them. They also like flat stones placed in the water, both at and just under the surface. During hot weather watch for falling water levels and adjust the exits accordingly.
Bird gardeners will welcome visits by kingfisher’s and grey herons, but the latter can be unpopular in gardens where ponds are stocked with goldfish and other ornamental species. Netting over the water is an effective way to stop predation, while erecting simple string or wire feature - an adjacent rock garden perhaps. This could also provide a simple waterfall system whereby water is pumped up and returned to the pond by gravity, producing oxygenation which is essential for a successful and productive pond. The alternative is to stock the pool with plenty of oxygenating plants, hornwort, for example.
A heavy clay soil provides a ready-made pond-liner which will cost you nothing other than a lot of sweat and toil. But soils with good drainage require entirely artificial techniques for which there are three alternatives. It is possible nowadays to purchase quite large, molded grassfire ponds which are excellent for the small garden. Their major disadvantage is that the size and shape is predetermined by the manufacturers. Preparing a concrete lining, and coating it with plastic paint, gives you much greater flexibility, but is laborious and, once completed, very difficult to alter in any significant way. Abettor alternative is to line your excavation with heavy-duty polythene sheeting, which is no more expensive than the other methods and is much more flexible in design terms.
At all stages of construction, extreme care must be taken not to damage or puncture the sheeting. It is important to provide a reasonably smooth base on which to lay the sheeting and then to lay it generously, to allow for its movement and settling when soil is placed upon it, and again when you add the weight of the water. Allow aide overlap at the edges and do not trim off the surplus until the whole pond is completed and filled. Again, are lines around the edges of the pool can also be an effective deterrent. Model herons or heron-like birds often make bird gardeners groan with distaste, but they, too, can prove quite effective deterrents in the short term. Fortunately, grey heron predation tends to be rather seasonal, at least at garden ponds, usually involving mainly young birds in late summer and autumn.
If the pond is lined, plants forth shallow edges to the pond should be placed in pots. Marsh marigold (1) is early to bloom, and its bright, golden yellow flowers can be seen as early as March. Water mint (2) is another attractive plant with pinkish flowers and fragrant leaves. Common reeds (3) will grow tall and form a good dense screen, but care must be taken as they could take over the area.
Edges of ponds which are damp and moist are ideal for plants such as stile (1), a plant with feathery plumes growing from30-90 cm/1-3ft high. Primulasof the variety pulverenta (2) whose stems are ringed with tiers of circular florets also like damp areas. Purple loosestrife (3), another plant of damp margins is especially attractive to bees.