What is the shape of the flower? Do the stems have any color other than green? How are the leaves attached to the stem? Is there only one stem or several stems, like guara?

The flower is rounded, but perhaps a bit more oval shaped than just a pink ball. It's not at all like guara (I just looked it up to be sure). It may help to know that I live in Minnesota so it's a Zone 4 plant. It is also not at all uncommon, but I am not a native of Minnesota so I don't know the local flora as well as I might. Also, I don't know what the leaves even look like. The flower stalk is pretty tall and I don't think it has any leaves on it to speak of. Thank you for being responsive!

How does it flower on the stem, one blossom at the end of the stem or many blooms along the stem? Does it bloom in the fall when many hydrangea shrubs are blooming or earlier when the Annabelle hydrangeas bloom? Are there many stems or a single stem?

Here are some fall blooming perennials, hollyhock (alcea), Japanese anemone, astilbe, purple coneflower (echinacea), Autumn Joy Sedum, daylily, liatris spicata, phlox paniculata, asters.

some annuals, salvia, zinnia,

Without more detail or a photo I do not have a clear idea of the plant.

I suggest that you stop and ask someone the next time you see it or goggle common Mn annuals and perennials and look through images to see if you can spot it then click on the photo which usually opens to a link with the photo and its name and often will link to a the place the photo was taken for more details.

Libraries are a great place to find books about MN gardening which usually have good identifying photos.

Oh, and please post again when you know the name so I can say to myself, "Of course it is."

Another thought, resurrection lily, naked lady. These grow a rosette of leaves which die off during the early summer. In August the bare stem comes up with a group of pink flowers on the end.

I'm familiar with Resurrection Lily and that is not it. It's not, I believe, a bulb. I have actually grown Resurrection Lily with much pleasure. Perhaps tomorrow I can get out and take a photo of it with my phone. Thank you for trying!

Well, the mystery is solved. It is Cleome. My husband took me for a drive this afternoon through many garden areas and I spotted it. When I got close enough to take its picture, the name came to me. The mind does odd stuff when it gets over 80 years old. Thanks for the conversation! Carolyn

Glad you identified it. I know how names escape our memory as we age. Thanks for letting me know.

Cleome LOL. I think everyone naturally thought of perennials not annuals.