A tree grows in Brooklyn.

And one pitiful tomato plant with four hopelessly tardy yellow blossoms pokes through a gravel bed in Chevy Chase in September.

When first I noticed it in July, I resisted the urge to pluck it out as if it were a common weed. Indeed, I considered it a Darwinian marvel. Its nearest kin had grown--badly--about 30 feet away last summer, yielding no more than a few dozen unimpressive and largely flavorless cherry tomatoes.

Perhaps some squirrel or bird had eaten one and left an organic calling card in the stones used by the previous owner's dog as a latrine and exercise run. Perhaps I'd dropped a slice of store-bought Roma or Beefsteak on the ground while grilling vegetables, and a seed somehow had taken root.

The means of germination did not matter nearly so much as the larger question: when--or, more to the point, if--the scrawny plant would bear fruit this year.

I confess I did very little to help the process along, although during the worst of the drought I did provide liquid refreshment in the form of recycled cooking water. When a friend suggested that corn kernels, rice grains and bits of pasta and potatoes could draw rats, I traded that particular mercy for an occasional dousing with water bailed by hand from my tub. But a green-thumbed chum gently suggested that Vitabath probably wasn't such a great garden additive.

Throughout August, I focused on the plants I cared about most: my mother's irises that line the front walkway; the blue hydrangeas whose color and shape I adore; towering double white hollyhocks abuzz with bumblebees.

I gave plant food and self-esteem pep talks to a traumatized pink azalea that a neighbor had uprooted and thrown out of her overgrown garden, careful to put it where we both can see it from our kitchens. Judging from its many new leaves, I think it may well live. I snipped the dead heads off exquisite coral roses, whose color exactly matched my first teenage lipstick, Revlon's "Snow Peach."

As the days got cooler and shorter, I zeroed in on the less cherished flora. That meant ripping out the morning glories growing like kudzu all over; hacking back an out-of-control wisteria that has never bloomed, in hopes that summer butchery would induce spring flowering; and dropping lots of rusty nails at the base of a pink hydrangea in the vain belief it might turn blue.

During that time, I never once thought about the tomato plant as it struggled upward between the gravel patch and the cement walk by the toolshed. It got watered when the rains came. Period.

But in recent weeks, as the rest of my garden wound down, I began to notice it, if only because it had somehow managed to survive drought followed by flood with no help from me. The other day, as I looked closer, there were--gasp--

nine tiny yellow flowers.

Now the equinox is just days away, and after it will come first frost. I have already decided that in between planting the fall bulbs--tulips, lilies and daffodils--and hosting a hosta party to give away a surfeit of shade-lovers, I will fight like hell to keep that little tomato plant alive.

I recently staked it and now water it regularly from an outside spigot. I feed it special food. During the worst of the recent winds and torrents, I added an extra metal truss. And I intend to make a burlap-and-slat shelter to protect it on chilly nights. Maybe, just maybe, by Thanksgiving--am I starting to sound delusional here?--it will bear fruit.

One lone tomato would be a glorious treat.

But in my secret heart, it really doesn't matter if there is no harvest at all. After taking time to smell the roses all summer, I have been given a lesson in survival. Even as the other well-tended flowers die, my little horticultural hero is fighting for life amid the rocks.

Ah, how seamlessly this "it" has become a "he . . . ro." Should I make that "he" a "me," Dr. Freud? Yes, for I have always identified with the underdog, the upstream swimmer. That's not a weed in my back yard. It's a need.

So, let those red and yellow and brown leaves flutter to the ground. They will make an ever-so-splendid blanket around that defiantly green tomato plant.