Jane Powers on her own private water world.
Few gardeners have much time to sit and stare at their handiwork. Contemplation, for the most part, must be left to others. However, in my case, there is one place in the garden that sucks me in with such a mesmerising force that sometimes I'm trapped for half an hour by its spell.
That place is my tiny pond, a self-contained watery world. Ever since the early-morning heron ate the last of the goldfish, and a nearby friend donated a family of tadpoles, it has gradually become a haven for all kinds of aquatic creatures. Fish, unfortunately, are destructive beasts, grazing both on pond plants and on fellow water-dwellers, such as tadpoles. A wildlife pond must be a fish-free pond.
And while I miss the "o" mouthings of my goldfish, they are nowhere near as interesting as the frogs. These normally shy amphibians lose all sense of decorum in spring, when they hop and flop en masse to the pond. There they take part in a very public free-for-all slow-motion orgy of sex-and-spawn which leaves blobs of eggy jelly floating in the water. Over the months the black dots encased in gelatinous goo progress to free-swimming tadpoles and eventually to pea-sized froglets - a dramatic metamorphosis.
Frogs lay their eggs in shallow water, but adult males may hibernate in the mud at the bottom, so a frog-friendly pond should be of varying depths - at least 60 centimetres at its deepest point if you are in a chilly part of the country. And, as the little froglings need to exit the water when they mature, a gently sloped side, or one with easily-negotiated levels, is essential. So also is the shelter of nearby vegetation, where they may hide from predators and from sun and wind.
A sterile band of slabs or concrete around a pond may mean death to baby frogs: ideally vegetation should come right to the edge of the water. Frogs move far beyond the pond, foraging for food (which includes slugs and snails). In winter adolescents and females hibernate in quiet, damp and shady places: rotting logs, crevices between stones, and under piles of leaves in corners. So don't be too concerned about cleaning up all the forgotten nooks and crannies in the garden.
If a pond is welcoming to frogs - with different levels, easy access and a mix of aquatic and marginal plants - it's likely that other water-dwellers will also find it congenial. Newts (if you're lucky), water beetles, pond snails, pond skaters, water boatmen, and a whole lot of other creatures may make their homes in it. If you're starting a new pool, a bucketful of water from a healthy wildlife pond elsewhere will set you up with eggs, larvae and near-invisible beings.
There are two things that make the the difference between a ham-fisted effort and a pond well done. First, get your levels right: nothing is worse than the tilted-bowl-of-soup effect, where one side of the pool is higher than the other. Except, that is, the second crime of water feature construction, which is the visible pond liner. Whether it's a precast fibreglass form or a flexible fabric, the lining should be completely concealed.
A wildlife pond, unlike some fish ponds (with all the extra nitrogen created by the droppings), is better able to maintain a natural balance. However, don't be shocked when a new pond turns to green pea soup overnight. This "algal bloom" is fed by the minerals in the water, and is perfectly normal. In a few weeks, the water will clear, when the aquatic organisms devour the algae.
Oxygenating plants (see below) also help clean the water, while floating plants and surface-covering species such as water lilies create shade and hinder algal growth.
Thin out excess growth of aquatic plants in late summer, and in autumn keep fallen leaves out of the water. Any fine day in winter you can cut down the dead vegetation sticking out of the pond (if you leave it until spring you might disturb the amorous activities of frogs and newts).
If yours is a frosty area, keep the pool open by floating a ball, or a bottle of salt water (which won't freeze) in it. If it does freeze, don't bash it with a hammer; this will not be welcomed by sleeping amphibians.
WILDLIFE ON THE WEB
www.froglife.org (all about amphibians)
www.hdra.org.uk/factsheets/gg29.htm (setting up)
www.hdra.org.uk/factsheets/gg34.htm (pond problems)
[ www.ipcc.ie/watergarden.html ]
ONES TO AVOID Invasive alien plants are fast-growing non-native plants that damage the natural ecology when they escape into the wild. The Royal Horticultural Society recommends avoiding the following (even though they may be sold in garden centres): New Zealand pigmyweed (Crassula helmsii, syn. Tillaea recurva), parrot's feather (Myriophyllum aquaticum), floating pennywort (Hydrocotyle ranunculoides), fairy fern (Azolla filiculoides).
DIARY DATE November 27th (10 a.m.-8 p.m.) and 28th (noon-5 p.m.) at Taney Church, Dundrum, Dublin 14: Christmas Flower Festival, with 15 floral artistry displays representing Christmas music. Admission: €8, in aid of Enable Ireland.
PLANTS FOR PONDS
OXYGENATING PLANTS keep water clean and healthy, by producing oxygen: water milfoil (Myriophyllum spicatum and M. verticillatum), water crowfoot (Ranunculus aquatilis), curled pondweed (Potamogeton crispus).
FLAOTERS can be dropped into the water where they provide surface cover, helping to exclude algae: frogbit (Hydrocharis morsus-ranae), yellow floating heart (Nymphoides peltata).
DEEP WATER PLANTS such as water lilies must be planted in special baskets, different varieties require different depths. Check the label to ensure a plant is suitable for your pond's depth.
MARGINAL PLANTS grow in the shallows at the edge of the pond, providing cover for creatures, and shading the water. Natives include yellow flag iris (Iris pseudacorus), burr reed (Sparganium erectum), marsh marigold (Caltha palustris), bulrush (Typha species). Among the non-natives are skunk cabbage (Lysichiton species), Iris laevigata and I. versicolor, monkey flower (Mimulus species), arrowhead (Sagittaria species), pickerel weed (Pontederia cordata), arum lily (Zantedeschia aethiopica).