The Philadelphia Flower Show

It takes one week; 7,000 Belgian blocks; 3,500 volunteers; thousands of plumbers, carpenters, and electricians; more than a million plants; and 50 tractor-trailer loads of mulch to transform the Pennsylvania Convention Center into the annual Philadelphia Flower Show (215/988-8899. www.theflowershow.com), the world's largest indoor horticultural event. But the exhibitors -- nursery owners, landscapers, and florists from the region and from Africa, Japan, and Europe -- spend the better part of a year planning their displays. The astonishing, fragrant results of their efforts arrive in the city as a touch of spring in early March.

It's a fitting tribute to William Penn that Philadelphia hosts this extravaganza, for this was Penn's "greene countrie town," which he laid out on a grid punctuated with tree-lined streets, pocket parks, small squares, and large public parks. It's also appropriate that this city gave root to the Pennsylvania Horticultural Society, the nation's first such organization. In 1829, two years after its founding, the society hosted its first show at the Masonic Hall in an 82-by-69-foot exhibition space; 25 society members showed off their green thumbs.

Today the show fills 10 acres of exhibition space at the convention center and spills throughout the area as local restaurants, hotels, and attractions offer special deals. (The show's Web site may have discounts and coupons.) Along with the more than 60 major exhibits, amateur gardeners contribute more than 2,000 entries in 330 competitive categories -- from pressed plants and miniature settings to spectacular jewelry designs that use flowers. There are free cooking and gardening demonstrations, lectures, and an area where you can try out the latest gardening gadgets. Hundreds of vendors sell plants, birdhouses, topiaries, watering systems, botanical prints, and more.

Each year, the show has a theme, and the show's designers think big -- very big. Visitors to the 2007 show, called "Legends of Ireland," entered beneath a living archway of flowers and ferns leading to the Ealain Wood, home to mythical creatures roaming under giant trees. The crystal-strewn Knot Garden, flanked by two fountains, led to the Castle of the Emerald Kingdom. This massive estate's exterior featured turrets, towers, and detailed stone work, while the interior offered a stage for live performances of traditional Irish music, dancing, and storytelling.

If you've made reservations, you can rest your weary feet during Garden Tea at the Flower Show (215/988-8879), a proper English tea served at 12:30 and 3:45. For a more substantial lunch break, you can head across the street to the Reading Terminal Market (12th and Arch Sts., Market East), which has more than 80 stalls, shops, and lunch counters. Or walk two blocks east to the many restaurants of Chinatown.

Many people plan trips to Philadelphia during the run of the flower show, so be sure to make reservations early. Wear good walking shoes, check your coat, and bring spending money for the many horticultural temptations. To avoid crowds, which can be daunting, arrive after 4 on weekdays and stay until the 9:30 closing, or show up when the doors open on weekend mornings, at 8.