The numbered bushes of Prospect Park?

They went down to the sea in ships, the Norwegians of old. Brooklyn, once part of a great seaport, naturally had Norwegian-American communities, first around Hamilton Avenue in Red Hook and later, and quite substantially, in Bay Ridge. But all that was before the war, as they say. Second and third generations went to the ‘burbs afterwards.

A.J. Liebling quotes the steward on the Norwegian tanker he came back across the Atlantic on in 1940"

“In Brooklyn I live in Hotel St. Yorge. Yentlemen! I don’t go on Court Street in Eyetalian saloons. I yust buy good old bottle aquavit and go to my room and drink like yentleman. Go to Norweeyan church Sunday and put five dollars in collection. Brooklyn women too smart. Better leave ‘em alone.”

The “kid from Brooklyn too young to die” was a stereotypical war movie staple in the 1940s and 1950s. Off Omaha Beach, Liebling introduces a couple of Brooklynites to each other:

“Brooklyn is a beautiful place to live in,” Fassy said. “I have bush Number Three at Prospect Park.”
“I used to have bush Number Four,” the soldier said.
“You remind me of a fellow named Sidney Wetzelbaum,” Fassy said. “Are you by any chance related?”

Numbered bushes in Prospect Park? Late 1930s, early 1940s. Anybody have any idea what are they talking about? Pete Hamill, Park Slope raised, edited this Library of America volume, but does not provide a note for this curious encounter, so I am dropping him an e-mail to see if he can fill me in. (No, I don't know him, but he's got a contact page on his site.) Stay tuned.