In this Madrid 'museum,' every masterpiece is green

I've never traveled to India, but I have stood in awe under a 90-foot Himalayan cedar. Wandering the tranquil pathways and greenhouses of Madrid's majestic Royal Botanical Garden, I've also marveled at cactus from Madagascar, shrubs from Siberia, tropical greenery from Africa, and wisteria from East Asia.

What good fortune that a break in a week-long spring rain led my husband and me to the imposing wrought-iron gates of this regal Madrid landmark.

Inside, we found an oasis of haunting beauty - a striking panorama of plants, trees, and flowers from five continents that captivated us with its grandeur.

The 18th-century garden is a favorite haunt of Madrilenos. It is not just one of Europe's oldest and most diverse botanic gardens, neatly compact on 20 acres, but it is set right in the middle of this frenetic, noisy city of 3 million. That makes it a cozy urban retreat, a no-stress zone for locals and visitors alike.

Few attractions in any big city are so wonderfully convenient and yet easy to miss. Abutting Madrid's main promenade, the traffic-choked Paseo del Prado, the garden is perfectly positioned near Madrid's three great art museums. Across a courtyard looms the Prado; the Thyssen-Bornemisza and the Reina Sofia are within a 10-minute walk. The elegant Ritz is close by, and the bustling city center, Puerta del Sol, but a few minutes away.

We came across this treasure almost by accident, as we emerged from a side door of the Prado to clearing skies one afternoon. A mere 100 yards distant sat the main entrance of the Real Jardin Botanico.

Over the wet days, we'd had our fill of wall-to-wall Goyas and Picassos, and now one look inside at the splendor of Eurasian trees and arbors covered with Chinese flowers had us yearning for masterpieces of the greener variety.

We weren't disappointed: 30,000 plants and 1,500 trees from hundreds of countries awaited us.

It's not necessary to be a botany expert, or even a garden enthusiast, to enjoy the flora and fauna as well as the fountains, statues, grape arbors, crammed greenhouses, pavilion art gallery, and flourishing fern and rock gardens.

One step inside and we were on the first of three themed terraces. Beckoning was a brilliant array of tulips in raspberry, crimson, orange, lemon, and luminous white. Nearby were trimmed hedge enclosures holding pink and red poppies amid patches of white pansies.

I was also drawn to rhododendrons from Japan and Korea and six-foot-tall Japanese camellia bushes with pink, salmon, and creamy white blooms. Their sweet, heavy fragrance was complemented by the delicate aroma of Chinese peonies with their yellow stamens peeking coyly through voluptuous pink petals.

Though spring had barely sprung, the garden was also rich with the sights and scents of daffodils, exotic red-flowered bushes with pods of white buds (Pieris formosa), white and burgundy hyacinths, European primroses, South African irises, and a pink and white European ground cover (Aubrieta deltoidea). Everything is labeled in Latin, with information in Spanish, sometimes English, also provided.

The garden's springtime tableau is especially dazzling, but summer, fall, and winter are also spectacular. Many of the flowers and shrubs bloom on the same schedule they do in their original countries, as if they maintain a nostalgic longing for - or irreversible genetic link to - their native lands.

The city's weather is an almost perfect mix of Atlantic and Mediterranean conditions that sustains everything from Tasmanian daisies and Manchurian geraniums to Canary Island date palms.

The garden is open year-round. While every season has its delights, May to August are particularly resplendent, as thousands of wild and cultivated roses from around the world bloom profusely.

Towering above them are the garden's magnificent trees. Among the lemon, lime, orange, palmetto, and apple varieties are hundreds more from a myriad of cultures and climates. Some have survived the Peninsular War (1808-14) and Spain's Civil War (1936-39).

Madrid, which is said to have more trees than any other big city except Tokyo, maintains a list of hundreds of Singular Trees of the Community of Madrid, which are outstanding for their bearing, history, and age.

I had never expected to see a pomegranate tree in Madrid. But there it was, 200 years old, 23 feet high, and sprouting fresh leaves when I encountered it at the end of a path. Equally exotic was a 75-year-old Japanese raisin tree that captivated me with its graceful bearing.

Towering above both was a 130-foot Caucasian elm. Each time I saw this native of the Caucasus, I marveled at its oval symmetry, conveyed by long, leafy branches soaring from a short trunk. Beside it was a Chilean Quillaja saponaria (soapbark tree). Gazing at them, I felt like a privileged traveler on a round-the-world botanic adventure.

A cypress - estimated to be 220 to 240 years old - is the oldest tree in the garden. It may have been here before the garden was established in this spot in 1774.

Beyond the dazzling flowers on the first terrace were kiwi vines and raspberry bushes, just emerging from their winter respites, plus vegetable patches and scores of herbal plants.

In 1755, King Ferdinand VI commissioned his botanist-surgeon, Jose Quer, to create the garden as a center for botanic studies and to grow medicinal plants for him and his subjects.

The garden was originally on the banks of the Manzanares River, south of Madrid, until 1774, when King Charles III bought land on Paseo del Prado and moved it for easier access. From its inception, the garden was open to the public.

Although the royal family no longer owns the garden, they attend important ceremonies and enter and exit through the King's Gate on the Paseo.

On the second terrace, among statues of distinguished 18th- and 19th-century botanists, are plants representing 12 evolutionary schools of plant life from the prehistoric era to the present.

The third terrace, designed as a classic romantic garden, became our favorite lunch spot. Toting bags of food, we'd make our way to the wooden benches around a small duck pond with a dignified bust of Carl Linnaeus, known as the father of botany, in its center. "Background music" was provided by doves and magpies.

I grew fond of these picnics - and the Royal Botanical Garden - but our vacation was coming to an end. Our final visit was on a Friday in mid-April.

A cool rain had intensified the garden's vivid hues and fragrances. The olive trees were sprouting new leaves; the wisteria was spreading rampantly onto a linden tree; and more pink blooms were apparent on the Himalayan clematis.

Walking through the gate, I sadly realized I wouldn't be back for a while, and thought of T.S. Eliot's line from "The Waste Land": "April is the cruellest month."

• The Royal Botanical Garden (Real Jardin Botanico) is at 2 Plaza de Murillo, Madrid 28014; Phone: 011 34 91 420 30 17; www.rjb.csic.es (in Spanish only).