Spring in East County is a time-release event. Like a well-formulated antihistamine, it unleashes its active ingredients gradually to prolong the effect. In the case of spring, those active ingredients are water and wildflowers. When buttercups begin to fade from the scene, poppies pick up the slack. And when the streams start going dry, along comes an infusion of rain, especially in this El Niño spring of 2010.

Round Valley Regional Preserve, located on Marsh Creek Road between the Highway 4 Bypass and Deer Valley Road, is East County’s late bloomer. Compared to the statuesque and glamorous chicks in her gang – Los Vaqueros, Black Diamond Mines, Morgan Territory and Mt. Diablo – Round Valley is petite and a little plain. Then May rolls around. The scrawny schoolgirl starts turning heads. When at the prom the glamour gals are dead on their feet, the wallflower flowers. The guys who’ve been snubbing her strut up and ask for a whirl on the dance floor. She says, “Take a hike.”

So we will.

We grab a map at the trailhead and head west on the Miwok Trail, where valley and blue oaks shade our way. Soon Round Valley Creek, one of Marsh Creek’s tributaries, begins serenading us with cooling music, hugging the trail here, passing under it there. The music never stops ... until we get to a left fork labeled Hardy Canyon Trail.

For some, it will be the Hardy Canyon Trial.

Though no Olympian ascent, the western leg of Hardy Canyon Trail is obstinately upward. Add the trail’s southern exposure to the equation and we have a recipe for perspiration.

The sight of wildflowers cheers us up. From a safe distance we admire the violet spikes of Italian thistle. We find bellardia, its white petals tinged in rose, plus magenta-hued clarkia, the wildflower poignantly nicknamed “farewell to spring.”

The trail swings south and east up the hillside’s graceful curves. On the second southward stretch we look right. There, between a gap in the rounded green hilltops across the valley rises another top washed in the blue haze of distance – Mt. Diablo. The higher up Hardy Canyon Trail we go, the higher the mountain in the west towers above its foothills.

The trail finally crests and we cut south across a grassy space up to the edge of a ridge where rows of protruding rocks provide a place to cool our heels. We’ve climbed from 220 to 1,140 feet above sea level. From here we understand how the park got its name. Far below glows a valley dappled in gold and green, encircled by the hills of Los Vaqueros, Morgan Territory and our own Round Valley.

We descend back to the main trail and look northeast, where a hill rising to 1,220’ marks the Round Valley summit. Those with a penchant for panorama – and a willingness to slog through the high and dry grasses – will find the extra elevation worth the sweat equity. From the top, gazing south we spot the hills of Ohlone Wilderness beyond Livermore. Our view west is dominated by the dramatic crags of Mt. Diablo. Northward lie the San Joaquin River, the Solano hills and, on a clear day, Mt. St. Helena anchoring the far end of Napa Valley. And snaking across the entire eastern horizon we behold the granite battlements of the Sierra Nevada range, its peaks heavy with snow.

We leave the overlook and reconnect with Hardy Canyon Trail. The finale of our walk is downhill all the way, starting with a short descent through grassland to an arroyo; then down into the trees and the enchanting realm of Hardy Canyon, where late spring’s assault on our senses resumes in earnest. As we follow the trail’s dips and turns, clusters of buckeye blossoms, perfectly nose-level, invite us to drink in their fragrance. Below to our left spills High Creek, while above to our right the canyon’s eastern slope is saturated with the piercing purples of bell-shaped Ithuriel’s spear and ookow rising on tall, thin stems. As the trail converges on the creek we see patches of monkeyflower brush the silver waters with bright yellow.

The home stretch of our loop takes us past Marsh Creek, its volume already on the wane. As the delicate petals of Hardy Canyon are destined to wither in the heat of June, so will Marsh Creek slow and shrink to a trickle. We’ve come to the beginning of the end of spring in Round Valley. But right now our wallflower is in bloom.

Save the last dance for her.