I never expect one plus one to equal two -- not in nature, not in life.

I've been told it equals two, but I grew up without seeing evidence to support the claim.

Consider grass seed. I've mentioned before how my mother, exasperated with our perpetually bare front yard, more than once scattered grass seed across its moonlike surface. We'd been encouraged, by both the grass seed bag and the lawns of our neighbors, to expect grass to grow.

But grass never grew in our front yard. The most the seed ever did was make the barren ground look as if it were covered with uncooked Cream of Wheat. Not a blade, not a single green spear ever emerged to give the yard a lawn-like look.

On to zinnias. My mother liked zinnias, presumably because they're unpretentious, low-maintenance, girl-next-door blooms.

She planted seeds from packets picturing tall, vivid flowers, and, inevitably, what emerged from the soil were unpretentious, low-maintenance, girl-next-door stubs. Lima-bean-sized buttons. Stemless blooms, basically.

Again, I drew my own conclusions: Whether you bury flower seeds or marbles, the results will be the same.

So last year, when my husband planted two batches of milkweed, hoping to bring monarch butterflies to our yard, I appreciated the thought, but I wasn't counting my butterflies before they eclosed. (Yes, eclosed. I just learned it.)

At first, my expectations were met. The milkweed stood there, alive and well, but as empty as college dormitories in the summertime. No caterpillars crawled on their smooth green fronds; no little jaws chewed lacy holes in the leaves. They looked like a party waiting for the guests to show up.

And this summer, they showed up.

From the start, the milkweed seemed taller, lusher, and somehow more ... come-hitherish. If last year it sat at the window, this year it was out on the front porch, waving and blowing kisses.

And they came. A small army of yellow-and-black-striped caterpillars are eating the milkweed, one caterpillar per broad green leaf. Sometimes the caterpillar is on top of the leaf; sometimes the leaf is on top of the caterpillar. Gravity means nothing to a very hungry larva.

The sight of these caterpillars eating as if their lives depended on it -- which they do -- caused me to undergo a metamorphosis of my own.

Suddenly, I doubted everything I thought I knew. It was like a dream when you realize you can fly. All you need to do is jump, and up you go. Even my husband, for whom grass and flowers always have grown, was thrilled.

Of course, monarchs' very existence is miraculous. The caterpillars eat one food -- one -- which would be challenging enough if the one food was grass or plastic bags or kibble. But milkweed? How do they find it? They don't have GPS. Or Burpee catalogs.

If I could, I'd describe the monarch's life cycle, including the 3,000-mile migration.

If I could, I'd go on and on, even though I'm sure you've heard the monarch story almost as often as middle school students have read "Hatchet."

If I could, I'd ignore your attempts to stop me and insist on telling it anyway, but I can't. I can't even explain the difference between second cousins and first cousins once removed.

The monarch saga is best left to lepidopterists, who can explain about the four stages in one life cycle and the four generations in one year without getting a headache.

Here's a fun fact, though: If you see a group of monarchs fluttering around, you can say, "Look at that rabble over there!" Yes, rabble. Or you can call them a kaleidoscope. A kaleidoscope of butterflies. From the ridiculous to the sublime.

Meanwhile, I'm tending to my own transformation, from lifelong skeptic to all-in believer. Because if two nondescript milkweed clusters can lead to monarch butterflies using my yard as an on-ramp to their destiny, who am I to doubt any other small miracles of nature?

Tomorrow, I think I'll grow some grass.

Write to Margo Bartlett at margo.bartlett@gmail.com.