Sources
https://extension.wvu.edu/agriculture/horticulture/elderberry
https://www.britannica.com/plant/elder-plant
https://www.fs.usda.gov/wildflowers/plant-of-the-week/sambucus_nigra_l.shtml
https://realgardensgrownatives.com/?p=4031
https://www.paganpens.co.uk/the-oghma-calendar
https://chris-anne.com/portfolio/ogham-ruis-elder-tree-r/
https://treesforlife.org.uk/into-the-forest/trees-plants-animals/trees/elder/
https://www.countrylife.co.uk/nature/history-elder-tree-deities-dryads-shakespeare-j-k-rowling-197720
https://ghostarchive.org/archive/fI41K
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347422/
https://www.stgermainliqueur.com/articles/the-curious-history-of-elderflowers/