Gladys Chappel uses a cane to carefully walk down the steep concrete steps that lead from her Upper St. Clair home to the garden.

There are lots of plants that look familiar -- peonies, phlox, butterfly bush and lots of other perennials. But as she turns from the stairs, she meets a mystery: a 5-foot tall plant surrounded by white plastic lattice.

The 86-year-old has lived here on Boyce Road since 1944, when she moved with her husband, Howard, to help take care of her aging grandparents.

Her grandfather, William Ladley, liked to visit a bar in Lawrence, Pa. There, he befriended an Italian man who gave him seeds of something he called "French beans." In 1950, Mrs. Chappel planted the seeds, and ever since the plant has returned each season, sprouting from its roots.

During the summer, the plant is covered in tiny half-inch purple flowers that turn into a seedpod reminiscent of soy beans, but these don't look edible and stick to clothes if you brush up against them. They eventually get to be 4-5 inches long.

"No one seems to know the answer, what they are." Mrs. Chappel said.

She's taken the flowers, leaves and seed pods everywhere she can think of and still can't get answers about this odd heirloom. She keeps a notebook filled with correspondence about the mystery plant.

"I'm just curious why it's lasted so long," she said with a smile.

Doug Oster writes a blog, "Growing With Doug," exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.