The trouble all gardeners encounter is compromise, and the more the gardener knows and loves plants, the harder the decisions are.

It's a great help if one knows very little--this is true in life generally--sparing one the common anxiety of awareness and understanding--since then the gardener can plow up what land he has and concentrate on marigolds.

It is harder if his taste is catholic, his curiosity is rampant and his dreams are not yet bridled.

Which brings me to a plant I think I have mentioned before, Nymphaea gigantea, a fine wild violet-blue water lily from Australia and New Guinea.

I have it in bloom in a pool that is much too small for it. I had a choice, in planting this wonderful flower, to grow it in a space too small for it (it occupies l00 square feet), in which the most beautiful effect is quite lost, or to steel myself not to grow it at all.

The thing I could not bring myself to do was to grow it on starvation rations. If I had done so, it would have fit in the 10-by-12-foot lily pool fairly well.

But if treated reasonably, given a half-barrel of good heavy loam, it really needs a water surface of 300 square feet to look good. That is a pool 15 by 20 feet.

Of course it can be grown in a 6-inch flowerpot in a tub of water, in which it will produce a few pretty little flowers. And there are some gardeners who, having no greater resources, rightly make the best of things and grow it in cramped quarters.

Sometimes I fear I make all the wrong decisions. I refuse to starve it, and yet I do not have a large enough pool for it to luxuriate properly.

Properly is the word, since this water lily luxuriates, all right. By early August it spreads over the pool surface, its yellowish-green pads covering a space 10 by 10 feet. It would willingly cover more than that, except its poor leaves keep ramming into those of other water lilies.

The way to grow this great flower, I well know, is to give it its half-barrel with one foot of water over it, in full sun, with discreet dosings of high-nitrogen fertilizer about the middle or end of July. I have not dared give it any stimulant, of course, lest it leave the pool and take over the dining room.

Pools look best if only a third of the water surface is covered with lily pads. Certainly no more than half the surface should be covered.

So this plant should have 300 square feet of water surface to show its best. And I know, even if I had a pool that large, I would not have the bravery to devote the whole pool to one plant that is at its best only in August and September.

Today there were nine flowers open. The stems rise above the water 12 to 18 inches, and the weight of the flowers makes the stems lean. The flowers open every morning for about five days. The insides of the cup-shaped or peony-shaped blooms are almost white, but the rows of outer petals are medium violet, blue enough to make such "blue" nymphaeas as 'King of the Blues' look positively purple by comparison.

The gigantea flowers have a curly mass of brilliant canary-yellow stamens in the center. The petals are stained a deeper color at their tips.

This might be the place to say that 'Pennsylvania' or 'Blue Beauty' (two names for the same plant) is undoubtedly the best blue water lily for the general sane gardener, having almost every merit and no defect. Or if a smaller lavender or blue water lily is required, the two best are N. colorata and, especially, the garden variety called 'Daubenyana.'

I've grown them, and some others, too, and I think I would not have got seduced by N. gigantea if the late Dr. Hans Conard, writing in 1904, had not issued the challenge that it is virtually impossible to grow as far north as Philadelphia, and that its beauty justified every trouble and every risk of failure.

Hmmph. I thought it unlikely it was that much handsomer than easier water lilies. I had seen it in New England (grown in a culvert adapted as a pool) and did not think it was all that remarkable, though the gardener up there did.

It is one of those plants that, once you grow them yourself, improve marvelously in beauty. You begin to see how sane men go to pieces over it.

To me, all other tropical water lilies are very nice, of course, and if one cannot manage the best, there is nothing really wrong with the others.

The flowers are full of honey bees, as well as various other bugs.

Despite its name, it is not the largest water lily by any means. Both Euryale ferox and Victoria amazonica make vastly larger plants. I have always had sense enough not to grow the huge Victoria, which covers at least 200 square feet of surface with its vast leaves, and therefore needs a good 500 square feet to look its best.

My bravery and discipline in turning down the Victoria, year after year, spring mainly from my view it is not a particularly beautiful plant, and its flowers, though a foot or so in diameter, are relatively (compared with other water lilies) plain. It is all very grand and sumptuous, but not to my mind very beautiful.

There is another blue water lily I go somewhat to pieces over, and it, too, is unfortunately quite large, and moreover does not bloom very freely, 'Mrs. Edwards Whitaker.' It is lighter than sky blue, the flowers a foot across and flat, and borne well above the water. I first saw it 49 years ago, fell in love with it, and have never grown it.

The trouble with N. gigantea, as far as I am concerned, is that it is irresistibly beautiful, to my eye. It has the further demerit (a demerit when one is bravely deciding not to grow it) of having the reputation of being quite difficult to grow, but in fact of growing as easily (once it starts) as any other water lily in the world.

I wish, sometimes, it were as difficult as Dr. Conard said it was. I suspect that (since he grew it well in Philadelphia) he liked to crow a little about it, and made it seem a greater triumph of good cultivation on his part than was actually the case. Gardeners are like that, I note with sorrow.

Aquatic specialists either stock it or easily could. In Washington it should be planted in the outdoor pool in mid-June. It does best in fine summers like the one we are now enjoying. It likes wholesome heat and sun. It is everything I ever wanted in a water lily and year after year (it is a pain in the neck trying to nurse it over winter in a foul-water big aquarium) it enchants me.

How much better if it refused to grow, refused to winter over in the aquarium, refused to bloom well.

Then I could count it among my failures, forget it and keep my garden pool in great beauty, with four moderate water lilies and the bright carp and the terrier pawing the water from the rim. In other years my pool has been that way.

Not now. Now I have the enormous gigantea. To feed the carp, I have to move a few lily pads to the side; there is not even enough bare water surface to feed them. I also lose all the beautiful reflections of the sky. I have lost, in other words, almost the whole reason for having a lily pool in the first place.

But when I peer out my bedroom window, or lug the old hound out (she has a disc problem in her back and has to be lugged about), I head for the pool in the first golden warmth of that sun that is a particular glory of our summer here. There may be seven or nine or no telling how many violet flowers on long stems, at various angles, with the bees busy and the dragonflies hovering and the carp thumping on the lily pads commanding to be fed.

The gardener has to compromise, has to give up things. I have made the wrong compromise, with the gigantea. I have given up too much.

And I am (water lily-wise) a supremely happy man.