Earlier this month, while perched on the couch with late-winter flu, I glanced at the shutters and noticed that each open slat framed a perfect rectangle of green.

I wasn’t sure where all that green was coming from. All winter long, the landscape beyond the window had been a bland palette of brown, beige and gray.

The spectacle teased me off the couch and to the window, where I discovered what was brightening the view. Our huge sycamore, bare all season, now sported a new canopy of leaves.

How had such a vivid transformation happened overnight? The change must have been pretty quick, or so I thought, because there was no way I could have missed such a shift in the skyline the past few days. Our sycamore is the biggest thing in the yard, its crown shading us like a circus tent.

But no tree moves from winter to spring in just a few hours. I had, in fact, somehow overlooked the clearest sign in my small part of the world that the year had turned.

And truth be told, I’d probably still be unaware of the sycamore’s new color if the flu hadn’t grounded me for a couple of days, slowing me enough to notice what was in front of me.

Between Christmas and New Year’s this winter, I read an essay by Sven Birkerts called “Strange Days,” in which he comments on a similar experience during his convalescence from surgery. Stuck at home, he suddenly had the luxury of seeing what the daily grind of obligation usually compelled him to ignore — the way the sun travels across the room or the house creaks or two squirrels climb “in some strange figure eights around the trunk of the maple.”

Birkerts’ altered perception points to a paradox — that oddly, being sick can make us feel more alive. “Don’t we turn back with some nostalgia to those sickbed days from childhood?,” he asks. “Not just because we were cared for, indulged, but also because of how in that widening eye of time the blankets became entire landscapes, and great cloud caravans moved so slowly outside the window.”

These days, as part of an assignment, I’ve been reading about Henry David Thoreau, the odd duck who avoided regular employment so that he could pay more attention to things like the changing seasons. He’d walk for miles to see the first seasonal bloom of a wildflower, but even Thoreau confessed that it was impossible not to miss stuff. “No mortal is alert enough to be present at the first dawn of the spring,” he wrote, “but he will presently discover some evidence that some vegetation had awaked some days at least before.”

With spring, time seems to move more quickly. But Easter, if we are lucky, brings a small pause, a look around, then gratitude for the greening year, and the winter world shaking itself awake.

Follow Danny Heitman on Twitter, @Danny_Heitman.