I have absolutely no idea. Go ask Alice.
But I can tell you why a garden is.
It was a hideously hot and humid summer here in the Midwest, and didn't we let our gardens languish and the weeds grew out of control? Oh, the area immediately visible from the deck where, of an evening, we sit and sip and enjoy the small, controlled back yard stayed well maintained and lush. But the areas not immediately visible (to us..the hell with the neighbors) began, by summer's end, to look as though no one lived in the house. The once beautiful clumps of black-eyed Susan and hardy ageratum spread their mats of roots and choked out most everything else. The walkway disappeared as the overgrowth flopped over. But it couldn't be left that way going into winter, or spring would be a disaster. So we go back to what was once a clean slate and begin, foot by foot, day by day, to dig up the intruders, throw away the invaders, carry huge clumps of matted soil to the curb for pickup. Then there's the trimming back of shrubs, some now, some that wait until spring. And, when the beds are cleaned up and the perennials cut back, we remember the ones that were too crowded and cramped and needed digging up and dividing, so we dig up and split them, and replant them in new places. And, while the back aches, and there's more, still, to do, there's satisfaction in the doing, of seeing things that didn't work in one place, that were dug up and moved years ago, thriving now, creating structure and bones. And being able to see how pieces that were out of place are now filling in a space that needed them. Oh, and the immense pleasure of giving the heave-ho to what was once beautiful, but no longer belonged in the total picture.
So it is with a manuscript in progress--and I've come to believe, having "finished" my novel several times, only to go back, when I (or another pair of eyes) step back and see it as a whole, what is working and what isn't, that every manuscript is a work in progress. At least until a publisher says it's done, or we give up, shelve it, and move on. As "they" say, writing is rewriting. No garden is static. If left alone, it takes on its own dynamic, reverting to what nature prefers. But we tease it, pluck it, move one thing here, remove one there, and when it looks just right, we sit back and enjoy it. Until we see that this shrub would do better over there with more sun, and that one is going to get too big for where it is, so will be better moved to the back. Oh, and what was back there will get more water and flourish in the space the other moved from. Editing can be like pruning a shrub, getting rid of extraneous words, words with the wrong tone, unnecessary phrases. But the real rewriting, revising (re-vision-ing) comes with digging up the huge clumps that, while lovely at first, no longer fit or belong, taking the scene that broke up another scene and moving it later, or earlier, combining it with another, and stepping back to see the shape as the elements relate to each other.
A garden is never finished. Even if it has periods where it can be just tended, eventually things will outgrow their space or die, and there are always new temptations to include. Books will, at some point, be finished, whether by publisher's decree or banishment. Another will be begun, and the process begins again. A different structure, or a variation. A new bed to plant. A new story to tell. And then the digging, moving, replanting, and pruning that goes into telling it.