|In Michigan, my mom always had a plant she called a Night Bloomer. This plant self seeded itself with small tiny black seeds that came from the inside of the flower which was yellow. This plant would start to bloom at early dusk and we would watch it bloom into a beautiful flower taking maybe 1/2 hour to complete. By morning it faded. Some nights, many blooms came to life. It came up each year. Mom has now passed away & no-one has any idea the name of the plant.
|There are some types of Oenothera that are commonly called evening primrose and one of these could be what your mom grew. They tend to have yellow blooms that open magically in the evening. Thompson and Morgan offers seed of one variety,
and as shown at the following page from Rutgers, some of them are considered weeds -- or wildflowers as the case may be. The one on this page is a biennial, meaning it would grow for a year, overwinter, then bloom the second year. If grown all in a patch, it could seem like the same plant coming back every year.
You will probably need to cut and paste the url into your browser to make it work correctly. Unfortunately, I can't tell you specifically which one your mom had but I hope this gives you a place to start.