HEISLERVILLE, N.J. - John DiOrio, a corrections officer in a minimum-security prison, no doubt enjoys his eight-acre retreat in this tiny town - grandly named the Maurice River Botanical Gardens and Reserve - as much as any du Pont ever did his topiaries and parterres.

Gardens are like that - democratic with a small d.

But DiOrio also believes gardening is in his blood. He's Italian on his father's side and part Lenni Lenape on his mother's side, and the mix looks something like this: respect for land, love of nature, and appreciation for anything native, rare or endangered.

"You like to make your mark in life, you know, and leave something for your kids. This is where I make my stand in New Jersey," says DiOrio, who's been building up his garden in his spare time for more than 17 years.

For the last eight years, he's opened it to the public just once a year, on the final weekend in August, when the region's ruby-throated hummingbirds mass to launch their journey to Central America or Mexico for the winter.

This year's event is tomorrow and Sunday, and though DiOrio had as many as 2,000 (human) visitors one year, you might need a hummingbird's compass to find him.

Situated just a half-hour west of Ocean City, this garden is as good as secret. With no road signs, no numbered mailbox, and only hyper-local advertising, few outside this rural pocket of Cumberland County know it exists.

As for staff, DiOrio's pretty much it, despite a bad back and other health issues, with help from his wife, Sandy, and son John. But everyone has a life, which comes first.

"I always felt career was about money, not love," says DiOrio, who describes his prison job as "not the easiest. Sometimes things really trouble me.

"The garden is my escape," he explains. "It's the great sanity."

DiOrio, who grew up in Camden and Collingswood and has three children and two grandchildren, has always loved tropical plants. "They look neat," he says, "and who wants to go to Florida every year?"

DiOrio notes that temperatures in these parts haven't dropped below zero degrees in 15 years. "Virginia Beach weather," he calls it, and it allows his warm-weather plants to survive New Jersey winters.

"Global warming does exist!" DiOrio declares.

He's filled his garden, part of 22½ acres that he and Sandy bought in 1989, with a little of this and a lot of that, randomly arranged.

DiOrio's holding off on a formal garden design until he can afford some greenhouses; he wants to do some propagating and more collecting from Brazil and the Florida Keys. Till then, he plants things where he plants them.

He has Japanese native cycad and Canary Island palms, hardy and tropical bananas, and eucalyptus. There's a giant clump of sugar cane from China; bog sage from Argentina; and, from Oregon, a couple of monkey puzzle trees, known for their weirdly splayed branches and blood-spilling needles.

See this prickly pear cactus? Grown from a single pad washed up on the beach at Cape Hatteras, after Hurricane Gloria in 1985.

And this cholla cactus? Looks like sculpted ballet dancers, but the shiv-like spines are almost impossible to remove from shins and fingers.

"Don't get too close," warns DiOrio. (Not a problem.)

He crunches the leaves of Cestrum 'Orange peel,' releasing a citrus-y blast, and shows off the splashy blooms of Salvia microphylla 'San Carlos Festival' from Mexico. He points out a blue Mediterranean fan palm from Morocco's Atlas Mountains, a Bulgarian needle palm, and American native pines, including pond, slash, spruce, Virginia, and loblolly.

While he's never studied horticulture, DiOrio is quite the student. In May, he began hosting a local radio show - Gardening the Garden State - Saturdays at noon on WVLT-FM (92.1). "Nature is a funny thing. It's not a textbook," he says, even as he rattles off botanical names, plant histories, and the provenance of every inhabitant of his garden.

Viola Carson, of the Cumberland County Cooperative Extension, enjoys DiOrio's eclectic approach and welcoming way.

"If you want to learn how to use less water and pesticides, and want to invite nature in, the whole ball of wax, John just knows so much about it," she says, "and he's invested. He's not just a homeowner who's interested in butterflies."

DiOrio mostly grows from seed, like the date palm that began as a pit and the parasitic mistletoe embedded in tree cambium. "To think this half-inch acorn can become a 100-foot tree . . . that's the greatest investment in nature we can make," he says.

Nature has bestowed a few critters on the property: deer, coyotes, groundhogs, meadow voles, star-nose moles ("very funky," DiOrio says), and rabbits. None can differentiate a precious Franklinia tree or rare rhododendron from ordinary chow.

More welcome are the Western tanagers and feisty hummingbirds, the monarch and giant sulphur butterflies. The habitat is rich here.

"The garden teaches people to respect life a little better," DiOrio says. "People run over box turtles on the road and think nothing of it."

He waters by hand, using a snake pile of hoses. To help tropicals ride out the winter, he gently covers them with rocks, then shredded-bark mulch. And he uses no synthetic chemicals; if something dies, it dies.

Speaking of which, DiOrio's riding mower has just given out, less than two weeks before the hummingbird festival. He's heading out to buy another one, suggesting yet another unwritten rule at the Maurice River Botanical Gardens and Reserve.

There's no endowment to support this place - just good ol' Bank of DiOrio, the closest thing to a blank check in the wild.

If You Go

This year's hummingbird festival at Maurice River Botanical Gardens and Reserve is scheduled for 10 a.m. to 4 p.m. tomorrow and Sunday at 28 Main St. in Heislerville, Cumberland County. Donation requested: $4. Also, from late spring till first frost, owner John DiOrio gives private tours of his garden by appointment. He likes to have a week's notice. Information: 856-785-2552.

Contact gardening writer Virginia A. Smith at 215-854-5720 or vsmith@phillynews.com.