Spring will finally arrive at the National Garden next month — nearly 16 years after Congressional lawmakers first planted the project’s seeds.

The Architect of the Capitol’s office recently signed a $9.2 million agreement with Maryland-based Walsh Construction to begin work at the 3-acre site situated between Maryland and Independence avenues on the grounds of the Capitol’s West Front.

Initiated by the 100th Congress in 1988 as a memorial to the institution’s bicentennial, the project has been dogged by repeated setbacks — ranging from the unexpected death of a former executive director to slowed fundraising after the 2001 terrorist attacks — which pushed back its planned opening more than a decade.

Even a ceremonial groundbreaking at the garden site in 2001 produced little fanfare, coming only days after the anthrax attacks on Capitol Hill.

More recently, officials scaled back the garden’s original design — suspending plans for an environmental learning center and other features — citing concerns over costs.

Unlike other projects constructed by the Architect’s office, the garden receives no taxpayer dollars and is instead financed entirely through private donations.

The nonprofit organization established to gather those donations, the National Fund for the United States Botanic Garden, set out to collect a minimum of $10 million when it began fundraising in 1991. It now appears the group will need to collect nearly twice that amount.

“It’s been a tough climate for fundraising, but we closed the gap and we hit our first target,” said Stephen Ward, executive director of the National Fund for the United States Botanic Garden. An AOC spokeswoman said the garden’s opening is planned for summer 2006.

While the $9.2 million contract will cover a “basic garden,” Ward said — which includes rose, butterfly and landscape gardens, a lawn terrace and fencing — it skips a number of the design’s original features.

“To build it the way it was originally designed would be enormously expensive,” Ward said. Nevertheless, Ward adds, fundraisers are seeking to collect up to $9.3 million more to fulfill the garden’s design.

The largest portion, which Ward estimates at $6 million to $7 million, would go to the Environmental Learning Center. According to the fund’s Web site, the center would have an outdoor amphitheater as well as a “multi-purpose lecture hall, classroom space, [and] a library.”

Another $1.5 million would be needed to construct the First Ladies Water Garden, described on the Fund’s Web site as “an important symbolic element of the National Garden.”

“Mosaics at the pool’s bottom will create an underwater carpet of abstract forms,” the site states. “Dedicated to the First Ladies of the United States, the Water Garden recognizes these remarkable women and their notable service to our country.”

The Showcase Garden, designed to display “the great diversity of American plants” that grow in the mid-Atlantic region will require an additional $800,000.

If Ward can meet those fundraising goals during the next 12 months, he said, those three projects could begin along with construction of the garden’s basic features.

“Our short term objectives are to start to pick off those additional options on the garden,” Ward said, and later added: “I feel reasonably certain that we’ll get the Regional Garden and the First Ladies Water Garden this year.”

Among the major donors to the National Garden project is Teresa Heinz Kerry, wife of Sen. John Kerry (D-Mass.), whose John H. & Teresa Heinz III Foundation made a $1 million gift.

Additional $1 million donations came from Ames True Temper, Home and Garden Television, Lowes Home Improvement, and Scott’s Company, while the Allbritton Foundation gave $820,000.

A 1997 U.S. Mint commemorative coin program also raised $3.2 million for the garden.

Additionally, Ward noted, local garden clubs have been “enormously helpful” contributing a combined $1 million to the project.

“We probably tapped them out pretty much,” Ward acknowledged, “and we’re going to have to look to other corporate and individual donors.”