Garden Ponds are a great way to enjoy your California backyard

Fountains And Waterfalls The best effect is achieved when the water- fall connects two small pools. The pools and the connecting structure should be made at the same time, and the fall part should be leak- proof-a leaking waterfall is just as exasperating as a leaky pond. If there is to be more than one step, then the first step down should be, virtually, part of the upper pool, and the first step up part of the lower. The intervening area is excavated some three inches deeper than its finished surface will be and the slabs of stone set in the concrete before it hardens. A point to observe is that the water does not run over the sides of the fall. Ferns and other bog loving plants may be set along the fall and then if there is any overflow it will do the plants good.

A tap, hidden by tall marginal plants, supplies the initial flow of water. A mere trickle is sufficient for the small waterfall and the best way of using the overflow is to have a bog garden around the lower pool. If there is partial shade the effect is delightful. One final remark on waterfalls. Some time ago I was asked to enquire into the mysterious behaviour, and subsequent death, of the fish in a certain pool. It had been constructed about six months previously and was, to all intents and purposes, cement-poison proof. Yet the fishes behaved as though some powerful alkali was irritating their skins. A small waterfall had been constructed subsequently, above the pond, and this was made of concrete. The pond had been scrubbed with a strong permanganate of potash solution, but the waterfall had not and it was from this that the poison came.

Needless to say arrangements must be made with the local Water Board if either a fountain or waterfall is to be used.

In the upper pool of the waterfall there will be a certain amount of movement in the water and, while the ordinary oxygenating plants will not object, water lilies will not be at their best. They prefer still water and, although the movement may be only gentle, it is not advisable to risk losing choice plants. The wild water lily (Nymphae alba) and the King Cup (Nuphar luteum) otherwise the Yellow Water Lily, are found commonly in slow- moving streams in the country, and so are quite suited to such a situation. Nuphar advena, a North American relation of the latter, is also at home in running water.

There is one cultivated lily, however, that has a very hardy disposition and that may adapt itself to the upper pool ; it is Brackleyi rosea, a delightful plant with fragrant, rosy blooms standing well above the water. Unfortunately this is an expensive variety, the price being in the region of half a guinea.