There are two sure ways of keeping blooms open. You can place stems in a vase of ice water, and store them in the refrigerator until time to use them as decorations. You will find that the shock of the cold water will keep the blooms from ever closing again. Or you can let the blooms unfold to their fullest before cutting them, and then put a drop of melted paraffin or wax from a lighted candle at the point where stamens, petals, and sepals join. Hardening, the paraffin or wax forms an unseen but sturdy cast which holds blooms open. Either procedure keeps flowers at their loveliest for three or four days, with no loss of luster or fragrance.

A word of caution: Water-lilies set out in this way as decoration bear up well under heat and even a bit of handling, but a strong, sustained draft of cold air will kill them. So don't set them directly in front of an air-conditioning unit.

The best advice I can give you in the interests of an attractive pool is not to crowd it. This may be bad for business, but I am duty-bound to warn you that many new water gardeners overdo planting.

Here is a rule-of-thumb that may help. Figure your square-footage of water surface. An 8- by 10-foot pool, for example, gives you 80 square feet. Now remember that most water-lilies fall into one of three size classifications which I have indicated in the listings. Extensive growers cover about 10 to 12 square feet when mature; medium growers cover 8 to 10 square feet; small growers confine themselves to about 4 square feet or less.

Cover no more than half the pool surface with water-lilies. Leave room for some submerged, floating, and border aquatics. You also will want some free, clear-water space, for reflections on the surface are one of the principal charms of a water garden.

So, for your 8 by 10 pool, select only enough water-lilies to cover 40 square feet or thereabouts. This gives you more variety than you may imagine-four extensive growers, five or six medium growers, or as many as ten small growers.

As you will see in the water-lily listings, Nymphaea tuberosa and all its varieties, some of the odoratas, such as gigantea, and practically all of the tropicals are extensive spreaders. They quickly fill a large pool with a pretty pattern of foliage.

If you prefer small water-lilies, you will do well to consider Nymphaea odorata minor, N. tetragona, N. mexicana, N. Laydekeri rosea, and N. pygmaea and its varieties, particularly helvola. The day-flowering N. elegans and N. Daubeniana are among the very few tropicals with a small spread.

Hardly a day goes by at Three Springs Fisheries when we do not answer at least one letter from a customer who wants a water-lily with some specific and outstanding characteristic-the tallest, the widest, the reddest, the most fragrant, and so on. Here are recommendations in some of these groups.