ST. LOUIS • The city is getting serious about environmental planning.

After more than a year of gathering data, Mayor Francis Slay is hosting tonight and Wednesday the city's inaugural "Sustainability Summit," inviting experts and the public to discuss their hopes for St. Louis's future.

It is the first of three summits over the coming year, and will lead to a city sustainability plan - a blueprint guiding the city toward a more socially, economically and environmentally sustainable future, city staff said. A draft plan will be released for public comment this spring.

Two of the sessions this week - tonight and Wednesday night - are open to the public. Slay said he expects about 100 business people, residents, "sustainability practitioners" and city leaders to attend a private work session Wednesday.

"Our goal in this first summit is to hear from our businesses and our residents about their ideas for a sustainable St. Louis," Slay said in a prepared statement. "We want St. Louis to be in the forefront of urban sustainable practices across the country."

New York City neighborhood sustainability advocate Majora Carter will open the summit at 5:30 p.m. at the Missouri Botanical Garden's Ridgway Center, and will also guide a workshop at 6 p.m. Wednesday at the Missouri History Museum.

Both sessions are free and open to the public. Registration for both begins at 5 p.m.

John Norquist, former Milwaukee mayor and current president of the Congress for the New Urbanism, will speak at a private lunch Wednesday.

Former Chicago Mayor Richard Daley, credited with his city's re-greening, was scheduled to give the event's keynote address tonight, but cancelled a few weeks ago, city staff said. His wife, Maggie, was fighting breast cancer and her condition had worsened. She died late last month.