I didn't find in Dr. Duke's database, any information about the uses of Geum longifolium
Here is some basic information about Geum longifolium.
Geum longifolium basic info
Scientific Name: Geum longifolium (Maxim.) Smedmark.
Geum longifolium in other websites
Geum longifolium common names, economics importance, distributional range and more in the USDA GRIN website - See link
Search PubMed (US National Library of Medicine National Institutes of Health) for academic researches with the search term Geum longifolium - See link
See if there is something in Youtube on the term Geum longifolium - See link