WASHINGTON — Robin Sutliff's flower shop is redolent with the ingredients of a perfect wedding place setting: tall stands of white amaryllis, cala lilies imported from South America, summery clusters of yellow-orange orchids. When she imagines the many same-sex couples likely to tie the knot in Washington this spring, though, her mind settles on the humble hyacinth.

WASHINGTON — Robin Sutliff's flower shop is redolent with the ingredients of a perfect wedding place setting: tall stands of white amaryllis, cala lilies imported from South America, summery clusters of yellow-orange orchids. When she imagines the many same-sex couples likely to tie the knot in Washington this spring, though, her mind settles on the humble hyacinth.

"It's a pretty flower," said Sutliff, owner of Ultra Violet florist. "It smells good, and it's strong. It represents spring and new birth."

Legalized same-sex marriage in the District of Columbia is expected to be a financial boon for the city and for vendors such as Sutliff, who make much of their money on weddings, but who have struggled during the recession. District officials surmise that the regional economy could reap up to $22 million over the next three years as couples from Washington and elsewhere take advantage of the new law, and the Williams Institute, a think tank at the University of California at Los Angeles, estimates that the infusion could be $52 million.

But the betrothed are not lining up quite yet. The law is subject to a 30-day review period by Congress, and opponents have taken their objections to court. Although many expect the bill to pass unhindered this spring, couples say the memory of California's Proposition 8 remains fresh in their minds. The 2008 voter-approved initiative banned same-sex marriage in the state after it had been legalized, a setback to many hopeful couples and a stunning reversal to those who thought gay marriage was on the path to mainstream acceptance.

"We're waiting to make sure that it makes the 30 days. We don't want to do too much dreaming," said Mike Giordano, 42, of Washington. He expects to marry his longtime partner next year but has not made any plans.

Six years after Massachusetts became the first state to legalize same-sex marriage and long after same-sex commitment ceremonies have become routine, a robust industry has developed around what many say is a tradition that has special needs. Arlington, Va.-based GayWeddings.com, for example, sells dual groom and dual bride cake tops. Wedding announcements available on Outvite.com include interlocking hearts fashioned to look like the symbol for female.

Both Web sites reported an uptick in traffic from customers in the past few weeks.

"We're all ramping up in anticipation that this is going to be big for the wedding industry here," said Allison Britton, an Alexandria, Va.-based photographer.