Tennessee Smart Yards Native Plants
A comprehensive database of Tennessee native plants
Whiteflower Leafcup, Small-flowered Leafcup
Whiteflower Leafcup, Small-flowered LeafcupPolymnia canadensisPart to full shade, moderately wet to dry moisture level, loamy soil, prefers alkaline pH. 2-4 ft. height, blooms summer into fall, white flowers, may self-seed in optimum growing conditions.Germination Code: C(60)Native Region: Statewide except absent in Coastal Plain ProvinceA member of the Aster Family. Woodland wildflower with striking large, deeply scalloped leaves and small flowerheads that are not very showy. Not very well known by the public. Native habitat is rich woods, usually rocky areas.flower;sun/shade;wet;loam |
 Photo Courtesy of John Hilty http://www.illinoiswildflowers.info/  Photo Courtesy of John Hilty http://www.illinoiswildflowers.info/ |
Tennessee Smart Yards Native Plants 
This summer I visited the Ijams Nature Center in Knoxville. Walking through their woodland, I was amazed to see what looked like Small-flowered Leafcup nearly covering the woodland floor, especially solid in any areas where the sun could peek through. It looked to me like it might be so aggressive that a person should be careful about planting it. Since I had planted a few plants in my small woodland, the sight made me a bit anxious. So I contacted the naturalist at Ijams and asked. He says that the forest floor is covered with both Large-flowered Leafcup and Small-flowered Leafcup, and the only way to tell the difference is when they are in bloom. He did not seem particularly concerned about the plants being aggressive, saying that “they form a good dense understory of lushness and it just depends on your space and how much room you are willing to let them have.” I thought I would add this comment because it might help someone who is thinking of planting this species. In the meantime, I am going to keep a sharp eye on mine because, personally, I don’t want an entire forest floor of this stuff.
Thank you.. 2 years ago I had a couple of plants of white leaf cup and this year it completely covered every inch of my wooded property and obliterated my lovely view of a waterfall.. I feel guilty pulling it up and I will keep some of it but yes this stuff’s aggressive!
Several years ago I also visited Ijams Nature Center and had the same reaction you did to the Small-flowered Leaf Cup. However, I ended up starting some from seed and planting plants in my little woodland, although I was a little anxious about it being aggressive. I don’t why but it did not spread. Several plants lived but that was it. I can’t explain the difference but it must aggressive only in the perfect spot.