Brimming with lime-hued succulents and a lush collection of agaves, one shooting spiky leaves 10 feet into the air, it’s a head-turning garden smack in the middle of Long Beach’s asphalt jungle. But the gardener who designed it doesn’t want you to know his last name, since his handiwork isn’t exactly legit. It’s on a traffic island he commandeered.

“The city wasn’t doing anything with it, and I had a bunch of extra plants,” says Scott, as we tour the garden, cars whooshing by on both sides of Loynes Drive.

Scott is a guerrilla gardener, a member of a burgeoning movement of green enthusiasts who plant without approval on land that’s not theirs. In London, Berlin, Miami, San Francisco and Southern California, these free-range tillers are sowing a new kind of flower power. In nighttime planting parties or solo “seed bombing” runs, they aim to turn neglected public space and vacant lots into floral or food outposts.

Part beautification, part eco-activism, part social outlet, the activity has been fueled by Internet gardening blogs and sites such as GuerrillaGardening.org, where before-and-after photos of the latest “troop digs” inspire 45,000 visitors a month to make derelict soil bloom.

“We can make much more out of the land than how it’s being used, whether it’s about creating food or beautifying it,” says the movement’s ringleader and GuerrillaGardening.org founder, Richard Reynolds, by phone from his London home. His tribe includes freelance landscapers like Scott, urban farmers, floral fans and artists.

“I want to encourage more people to think about land in this way and just get out there and do it,” says Reynolds, whose new handbook for insurgent planters, “On Guerrilla Gardening,” is out this week.

The activists see themselves as 21st century Johnny Appleseeds, harvesting a natural bounty of daffodils or organic green beans from forgotten dirt. It’s a step into more self-reliant living in the city,” says Erik Knutzen, coauthor with his wife, Kelly Coyne, of “The Urban Homestead” to be released in June. The Echo Park couple have chronicled “pirate farming” on their blog, Homegrown Evolution. Guerrilla gardening, Knutzen says, is a reaction to the wasteful use of land, such as vacant lots and sidewalk parkways. He’s turned the parkway in front of his home into a vegetable garden.

One of a slew of DIY gardening currents, such as permaculture (design of highly sustainable ecosystems), urban homesteading, composting and free fruit movement, guerrilla gardening is a response to dwindling green space, limited land and suspicions about food sources, say experts. It’s also part of a time-honored American tradition of gardening public spaces.

“It reminds me of the Vacant Lot Cultivation societies,” says Rose Hayden-Smith, a Food and Society Policy Fellow with UC Cooperative Extension. In the wake of the economic meltdown of the 1890s, many American cities, from Detroit to Philadelphia and Boston, formed Vacant Lot Cultivation associations to encourage residents to grow food on public land. The Liberty and Victory garden campaigns of World Wars I and II, respectively, also exhorted Americans to raise food on untended public land.

“If the federal government was paying attention, they’d be encouraging this right now,” with the price of food and fuel,” adds Hayden-Smith.

“Guerrilla gardens can serve the same purpose as the Victory gardens,” says Taylor Arneson, editor of the Los Angeles Permaculture Guild newsletter and a proponent of sustainable food production. He and a friend raised a farmers market worth of crops — corn, beans, squash, tomatoes, lettuce, watermelon, cucumber and more — in a guerrilla dig at a large planter bed in front of an office building on Bundy Drive in West Los Angeles. Farming in broad daylight, they got support from office workers and kids excited to see real cornstalks.

Arneson’s approach is to plant first and make arrangements with sympathetic locals to hook up to water taps later. Keeping a guerrilla garden irrigated is one of the trickiest parts of the game. Arneson, a graduate student in village-scale permaculture design, says he rules out 99% of the vacant lots he scouts because they don’t have a reliable water source. He looks for some elevation or berm that will let the plants catch water.

After more than a year of growing crops at the Bundy site, he and his friend planned to live on the produce grown there last winter. They planted garlic, potatoes, radishes, carrots, lettuce, onions and more, but in January the owner of the property, after first leaving a cease and desist letter, rototilled the whole plot.

Property owners who don’t take kindly to others gardening on their land have laws on their side. But most freelance growing is done in the nooks and crannies of public land, where the law is murkier. Spokespersons at the Los Angeles city departments of Public Works, and Recreation and Parks were unaware of laws proscribing citizen gardening in public spaces. A patch of wildflowers on a city-owned lot wouldn’t be removed until it dried up and became a fire hazard, according to the city’s Street Services’ Lot Cleaning Division.

Back at that median oasis in Long Beach, Scott is making introductions. “This is Aloe nobilis. Put them in the ground and in five years you could turn out 10,000 plants,” he says. Scott may not have title to the land, but he tends it as if he did, weeding and pulling out trash — he’s found such debris as car parts and condoms in there. He’s bummed when he spots a bare patch. “It’s kind of depressing when I see how much work needs to be done,” says the Norwalk resident, who works for the government. “This whole section, there’s something in the dirt. This is old landfill and they probably just used that dirt.”

He built the garden up over a period of years, planting early in the morning to avoid detection. Police have questioned Scott at his traffic island during early morning plantings, part of the uncertainty that comes with guerrilla gardening. Several of his unsanctioned gardens along the San Gabriel River have been wrecked by agave thieves, who, he thinks, steal the leaves to make tequila. “You just take a deep breath and go back to it,” he says.

But homeowners in Long Beach have encouraged his work on the median. Today the garden is a veritable nursery. He’s taken out hundreds of plants incubated here, some of which he moves to unapproved gardens he’s planted and tends in Norwalk and Whittier. Why does he bother with all the work, expense and dodging authorities? “I’d like to show cities that they can use plants like these, not have to water as much and cut down on landscaping costs. Within two to three years, a site like this can generate thousands of plants.”

Scott sees his Long Beach garden as a showcase for drought-tolerant, low-maintenance city landscaping. But he’s in a bind. How does he broach the subject, given his unsanctioned status? “I wish I could get together with the city,” he says. “But I’m apprehensive and pretty much keep under the radar.”

Meanwhile, over at landscaping headquarters for the city of Long Beach, superintendent of grounds maintenance Ramon Arevalo waxes on about one of more than a dozen gardens done by “road planters,” as he calls guerrilla gardeners. “It’s like an underwater scene, a cactus garden that looks like a corral reef. It’s beautiful. It’s been there on Loynes Drive for 10 years, and we don’t know who did it. You should see this place!”

It’s Scott’s garden. I tell him I have seen it and know the mystery man who planted it. Arevalo is ecstatic. “I can’t wait to know him! He’s been the talk of this place for 10 years. He’s like the 007 of gardening,” says Arevalo, laughing heartily. He says a homeowners association has complained that their medians are ugly. Why can’t theirs look like that cactus island?

Arevalo is impressed by Scott’s use of drought-tolerant plants and assures there will be no repercussions if he comes forward. There is no law against planting on city landscaping, except for ficus trees, whose roots wreck roads and sidewalks. The city discourages unapproved gardening but tries to work with road planters it discovers. “If you want to do this, my advice is to contact myself or the council person,” says Arevalo. “We want to partner with people who care about where they live.”

At a time of shrinking city budgets and skeletal landscaping staffs, it’s a hint at where guerrilla gardening could go — to approved brigades of citizen gardeners helping cities turn wasted space into food and flowers. After years of looking over his shoulder, Scott can come in out of the cold dawn plantings. He has Arevalo’s phone number and attention.

“I’ll do whatever he wants,” says Arevalo, chuckling. “I want to buy him a coffee.”