Upland boneset seed collecting

Upland boneset (Eupatorium sessilifolium) is a relatively uncommon species (Special Concern in Wisconsin) that is found primarily in oak savannas or open oak woodlands. Originally we had only a fairly small population at Pleasant Valley Conservancy, but through our restoration efforts and transplants from greenhouse-raised plants, it has now become more widespread. The original population, which had only 5 stems, is now well over 100, and we also have it in at least five other savanna areas.

Although we have been able to raise plants, the germination rate from seed is surprisingly low (considerably less than 5%). According to a test I had run at the Seed Lab several years ago, most of the seeds were live but dormant (i.e., tetrazolium-positive).

Every year we make an effort to collect a substantial amount of seed, since we have the idea that one of these years the seed viability will be good and we'll get a lot of useful seed.

The photo here is from a small prairie remnant in southern Wisconsin which for some reason has a large population of E. sessilifolium.

Another species, tall boneset (E. altissimum), is more widespread, but these two species are quite easy to tell apart. The leaf structure on E. sessilifolium is quite different and once you see these two species together, you will never have trouble telling which is which. Finally, there is a wetland species, E. perfoliatum, with the stem perforating the leaf. Again, no trouble telling it apart.