At Kew Gardens, outside London, a lone Wollemi pine is locked behind a metal cage, with security personnel watching dutifully from a distance.

At Kew Gardens, outside London, a lone Wollemi pine is locked behind a metal cage, with security personnel watching dutifully from a distance.

It's been called the botanical discovery of the century.

It was 16 years ago this month when Australian outdoorsman David Noble went on a hike less than 100 miles from downtown Sydney. David and two companions descended into a deep, sheltered canyon in the rugged Blue Mountains. Exploring the remote canyon, he came upon a small group of odd-looking trees.

The trees had unusual bark that resembled bubbles of chocolate, multiple trunks, ferny-looking leaves and were up to 100 feet tall. Curious, Noble took a fallen branch home to show to Wyn Jones, a senior naturalist with the National Parks and Wildlife Service. After a cursory glance, Jones told Noble that he thought the branch was from a fern.

"No," Noble said, "It's from a bloody great big tree."

Two weeks later, the two returned to the canyon with Jones to see the trees in the wild. They definitely were not ferns.

After considerable taxonomic research by botanists at both the National Parks and Wildlife Service and the Royal Botanic Gardens Sydney, the tree was finally revealed to the world by Ken Hill, senior botanist at the Royal Botanic Gardens.

Three months after Noble first set eyes upon these odd plants, his discovery was declared. It was Wollemia nobilis, a new genus and species. The trees were instant celebrities, and the news traveled quickly around the world.

For botanists, the discovery of these trees was akin to finding dinosaurs alive on Earth — and only 100 miles from a major metropolitan center!

In all, the wild population was placed at 76 trees and 200 seedlings. Wollemia nobilis had been discovered — or rediscovered. Thought to have been extinct for 90 million years, it previously was only known from a few fossil remnants dating back as far as 150 million years.

It was named in honor of both the region and its discoverer. Wollemi is an aboriginal word meaning "look around you, keep your eyes open and watch out." Nobilis pays tribute to its discoverer, Noble. Wollemi pines are members of the ancient Araucariaceae family, along with better known relatives like the Norfolk pine and monkey puzzle tree. All are plants of the southern hemisphere, found in isolated populations in South America, New Caledonia, New Zealand, New Guinea and Australia.

The Australian government deserves great credit for its work to protect and conserve this rare species. The location of the pines is kept completely secret, and there is a $220,000 fine for anyone going near them. Only a very small number of researchers are allowed to visit the pines, and they must follow strict quarantine measures, such as changing their clothes upon entering the grove to prevent the introduction of weeds or diseases. Measures have also been taken to protect the trees from wildfires.

The cones on Wollemi pines are both male and female, with only the female cones viable for germination. Propagation of the tree has been tedious, and there was a huge buzz when the first cultivated trees were made available by auction through Sotheby's. It was like an international art auction. Botanical gardens and others with sufficient bidding dollars paid thousands for the first trees — and bragging rights. The highlight of the auction was $150,000 paid for 15 trees grown from cuttings of the original, wild trees. The average price per tree was $3,600. Royalties from the sale of these first plants were swiftly returned to fund further conservation of the Wollemi pine.

The first trees planted in public spaces were equally newsworthy and were placed only in well protected, high security facilities. It was actually quite funny to see these young plants locked up. I recall visiting Kew Gardens, outside London, a few years ago and seeing a lone Wollemi pine in the famous garden, locked behind a metal cage, with security personnel watching dutifully from a distance.

I was lucky enough to acquire a small Wollemi pine in December 2006, and I treasure it. Wollemi pines grow quite well in our Southern California gardens. Today, a handful of these incredibly rare plants are available at a few nurseries.

The story of the Wollemi pine is just one grand example of the need to conserve our remaining natural areas. You never know what you might find.

RON VANDERHOFF is the nursery manager at Roger's Gardens, Corona del Mar.

Ask Ron

Question:

What fertilizer do you recommend for feeding succulents?

Bruce, Costa Mesa

Answer:

Succulents are light feeders. Many general-purpose, balanced fertilizers can be used, but reduce the quantity 50% from whatever the instructions indicate. My best suggestion would be to use an organic fertilizer labeled for tomatoes. Succulents prefer a little additional calcium, as do tomatoes. The mild, slow feeding qualities of an organic fertilizer would suit succulents quite well.

ASK RON your toughest gardening questions, and the expert nursery staff at Roger's Gardens will come up with an answer. Please include your name, phone number and city, and limit queries to 30 words or fewer. E-mail stumpthegardener@rogersgardens.com, or write to Plant Talk at Roger's Gardens, 2301 San Joaquin Hills Road, Corona del Mar, CA 92625.