You've been making fun of Prince Charles for a long time now - the ears like open taxi doors, the fuddy-duddy mannerisms and marital missteps.

But here's something you probably don't know about HRH Charles Philip Arthur George, Prince of Wales: For almost a quarter-century, he has been a prescient champion of organic gardening, a famous, if lonely, voice in a wilderness once considered the preserve of wackos and hippies.

At long last, the gardener formally known as Prince is alone no more. Organic gardening is coming into its own.

The number of U.S. households using only all-natural or organic fertilizer, insect controls, and weed controls increased from about five million in 2004 to 12 million last year, according to the National Gardening Association's lawn and garden survey, done by Harris Interactive.

Most of the nation's 100 million gardening households still use conventional methods such as synthetic chemical fertilizer, pesticide, and insecticide, but the organic component is growing rapidly. And at least some of the credit goes to Charles, who has gardened organically at Highgrove House, the 21-room (plus nursery wing) Gloucestershire estate he shared first with Princess Diana and now shares with Camilla, Duchess of Cornwall.

It was bought for him in 1980, along with 1,100 acres of farmland, and he began his organic adventure five years later.

In books, interviews, and speeches around the world, Charles roundly rejects "the ever-available chemical conveniences" in favor of a "more balanced way of tending the earth." In this, he was heavily influenced by the writings of Albert Howard, a British botanist known as "the father of organic farming."

Howard also inspired J.I. Rodale, who founded the Soil and Health Foundation, forerunner to the Rodale Institute, in Emmaus, Pa., in 1947. The institute worked quietly with Charles to get his Highgrove farm and gardens going.

Today, Scott Meyer, editor of Rodale's Organic Gardening magazine, calls Charles "an icon who plugged on till he was completely right."

"I think his leadership reassured people that organic gardening was not crazy and that this moment could happen. In fact, we got to this moment because we had people who stood up for it," Meyer said.

Perhaps no one knows Charles' stand-up quality better than David Howard (no relation to Albert), who was head gardener at Highgrove for more than a decade. The two share the organic view of the world, and both, early on, suffered for it.

"People for a long time thought he was cranky, and my colleagues thought I was mad," recalled Howard, whose full-time staff of nine took care of 15 acres of gardens at Highgrove. He left in July, when he turned 50, not in midlife crisis but churning with desire to "send the organic message out to people."

"The tide is finally turning," he said.

Home-improvement chains such as Lowe's and Home Depot now carry an array of organic products, and companies such as Scott's Miracle-Gro Co., the world largest purveyor of conventional lawn and garden products, have organic lines.

This market segment is growing by about 13 percent a year, according to Keri Butler, Scott's public-affairs director.

Last month, as part of his new role as a consultant, Howard visited Bartram's Garden in Southwest Philadelphia to help North America's oldest surviving botanic garden reinvent itself in the new century.

"This place is a historical gem, a wonderful historic site," Howard said, "but it's a disappointing thing. The garden does not complement the buildings. I'd like to see the horticulture here elevated to the level of the history."

Like its 18th-century Quaker creator, John Bartram, the garden is modest. In that respect, it bears little resemblance to other public gardens in the Philadelphia area, which is known throughout the gardening world for the quantity and quality of its horticultural offerings.

No showy displays like Longwood Gardens near Kennett Square. No wild waves of color like Chanticleer in Radnor Township. No academic affiliation like Morris Arboretum in Chestnut Hill or Scott Arboretum at Swarthmore College.

And, alas, no du Pont money.

But that may be the secret weapon of this humble, 45-acre oasis on the western bank of the Schuylkill. Despite its location in one of the city's poorest and most violent neighborhoods, the garden enjoys unusual richness. It has both a million-dollar view of Center City and a deep-rooted botanical history that, at the moment, is more acclaimed in England than at home.

As he surveyed the realm, Howard reminded a visitor of his conversation boundaries. "I can talk all you want about gardening but not about the royal family," he said.

So nothing about Camilla, who tromps through Highgrove's wildflower meadow, stumpery, and sundial garden, which Howard redesigned, in plebeian jeans and blue sneakers and is feted for her floral arrangements in the house. And nothing personal about the longest-waiting heir-apparent, whom Howard unfailingly calls "the Prince of Wales."

We do know from elsewhere that Charles is hands-on in his garden, which he once said "delights the eye, warms the heart, and feeds the soul." Speaking of feeding, he likes to tend to the birds and ducks himself and prefers potatoes and brussels sprouts for himself.

He likes terra-cotta pots, scented roses, and geraniums, too. And we're told that he and Camilla spent much of their honeymoon personally installing the plants they had received as wedding gifts. For gardeners, this constitutes fun.

For Howard and his prince, the garden is endlessly fascinating, a lifetime of teachable moments. "Every plant has a story to tell," Howard said, his hand cupping a red tulip in front of Bartram's simple stone house.

In Bartram's time, he explained, Dutch tulips were the stuff of legend. Not unlike the spikes and crashes of the dotcom and subprime-mortgage crises of modern times, the 17th century had its speculative bubble, called "tulip mania."

Howard moved on to the yellow daffodil known as "hoop petticoat," an elegant little thing that looks like an upside-down ball gown. It dates to the 16th century.

History is everywhere here. "Telling the story is the most important thing," said Howard, whose ideas will be part of the garden's new 10-year strategic plan. It includes replanting the orchard; restoring the garden; moving the parking lot; adding 20,000 tulips, signs, and a greenhouse for plant propagation; and increasing the organic commitment.

Plans call for access to the garden by bike in 2010, by bridge in 2012, and by boat this summer. Visitors already can take a guided tour of the garden and house, and new lessons are being drawn up for schoolchildren.

"We're weaving David's ideas into our message," said Louise Turan, Bartram's executive director for the last 16 months.

"The kids don't just come here to churn butter," Turan said. "We take them out into the garden. They dig in the dirt and find a worm or some invertebrate. We talk about its relationship to the soil and the earth, the sky and plants. It's vitally important."

Organic gardeners prize a healthy, interwoven ecosystem. They enrich the soil with compost and other organic matter instead of synthetic fertilizers. They control weeds the old-fashioned way - with mulch and elbow grease - and consider most insects good guys, not "pests" to be nuked.

Organic everything is trendy now. Rockers Bruce Springsteen and Dave Matthews and British actress Elizabeth Hurley even have organic farms. Just last week, Hurley announced that her new organic meat and grain products would be among the 200-plus items sold by Duchy Originals, the organic-food company founded in 1990 by none other than Prince Charles.

Hurley may not be the only super-glam lady friend he's ever had. But she may be the first to share his appreciation for rotted farmyard manure.