The removal, which the horticultural society and others pondered long and hard, is necessitated by the age of the paulownia trees, officials said. At least some of the trees around the fountain date to the 1930s.
Groundbreaking for the landscaping project, which has recently been approved by various city agencies and is part of the first major landscape redesign of the square in decades, will take place on Sept. 15.
The work, funded through a $750,000 grant from the Pew Charitable Trusts and $400,000 from Fairmount Park, is part a larger effort under way to revitalize the Benjamin Franklin Parkway.
That effort, led by the Center City District, has already produced new lighting for building facades, sculptures, streets and sidewalks, and the installation of new traffic lights and crosswalks at Logan Square.
Design work is under way that could lead to cafes, bookstalls and other pedestrian amenities in the area around the square.
Designed by the Olin Partnership, the landscaping is expected to take about two to three months to complete. It will not affect the basic layout of the square, horticultural officials said. Sidewalks will be somewhat narrower, but most of the work will be focused on revitalizing the plantings.
In an interview several months ago, J. Blaine Bonham Jr., executive vice president for the horticultural society, acknowledged that the removal of the enormous paulownia trees could be an eye-catcher.
"This being comfortable Philadelphia, there's going to be a hue and cry when the beloved paulownias come down eventually," Bonham said. "But the intent will be to replace them with new paulownias."
"They've got to come down, or they're going to fall down," he said, adding that the overall design for the square would not be tampered with.
"The circle," he said, "is such a strong visual image with the fountain, it demands that its formality be retained."
Paulownias, he added, are very fast growers. Once the new trees are in place, they will rapidly reach substantial heights.
Contact staff writer Stephan Salisbury at 215-854-5594 or firstname.lastname@example.org.