For some Brooklynites, the dirt plots in their sidewalks where trees grow are like a blank canvas.

In August, the block of Warren Street between Court and Smith streets in Cobble Hill suddenly sprouted large, colorfully painted rocks, one in nearly each of the sidewalk tree pits — those small, often derelict patches of dirt or grass where dogs love to pee.

“It’s really about love more than anything else,” says Jennifer Michael Hecht, the local responsible for improving these tree pits. And people love her work — so much so that she’s been hugged by grateful neighbors, and a construction crew from a project across the street have started bringing her rocks from the building site.

Warren Street is just one place where bitty street art exhibits have popped up, lovingly installed by residents.

“We’ve seen people literally plop down in our tree pit and treat it like a minipark,” says Park Slope’s Sara Baysinger, 46. Two years ago, she, her husband Jerry, 47, and their sons Oliver, 13, and Ziggy, 16, created Teencetown — a homemade village populated mainly by plastic dinosaurs — in front of their then-home on 13th Street between Seventh and Eighth avenues.

The pit became a community affair, with locals and passers-by contributing and rearranging Teencetown’s residents and tiny wooden shops, which include “Littleman’s Bakery” and “Small’s Grocery.”

Not all of the development was successful.

“One of the neighbors thought he was doing something fun and he put a candle in the tree pit, and the thatching on some of the roofs caught fire,” Baysinger says. “He wrote us a lovely note with an eloquent apology.”

Since her family moved to North Carolina, a young neighbor was charged with overseeing Teencetown. Alas, it’s recently fallen on hard times, with many of its residents gone and its shops vandalized.

Hecht says she’s had a few of her painted rocks disappear since she began installing them three years ago. “I go with bigger and bigger rocks so people can’t steal them,” says the 52-year-old writer, who paints them with her husband and kids, ages 12 and 14.

The trend has spread across the borough, with decorative pits popping up on Columbia Heights in Brooklyn Heights (a mini Lady Liberty and the Twin Towers) and Troutman Street between Irving and Knickerbocker avenues in Bushwick (a Teencetown-esque toy community).

Fourth-grade teacher Lisa Dewhurst, 54, has been dressing up sidewalks since 2008. The Carroll Gardens resident built a miniature wooden Brooklyn Bridge for her father, Ted Kaufman, who lives on Clinton Street between Warren Street and Verandah Place in Cobble Hill, before making another to sit in front of her own home on Fourth Place near Court Street.

Dewhurst has since replaced her dad’s — “Kids play on it and dogs pee on it,” says Kaufman, 84 — but she says it’s worth the effort, just to see people stop and gawk. “That makes me so happy,” she says.