Evergreen plants are powerful indeed. Cherokee lore tells us that the Great Creator, after creating All Things, had but one thing remaining to be created: The Human Race. In order to procure the necessary energy, Creator asked all creatures and creations to fast for four days (seasons) to send energy back that humans might be created. By the fourth day (season), only the evergreens had enough power left to remain strong and green.
If you doubt the power of herbs and oils, consider this inspired example of nature's fierce grace.... Many of nature's most powerful blessings aren't a part of our herbal apothecary because of their threat to life even with minimal ingestion--herbs like foxglove, poison hemlock, and deadly nightshade are just too potent for us to be playing around with them. Yet many of those same herbs have had their active components isolated in laboratories for use in microscopic quantities in pharmaceuticals--and to great effect. Pharmaceutical companies rely on a component sourced from foxglove to manage heart rate, that from poison hemlock serves as an antispasmodic and sedative, and a component of deadly nightshade addresses acute cardiac arrest. Even common aspirin was informed by the naturally occurring acetylsalicylic acid in willow.
Whereas many essential oils have a shelf life limited to just a few years under even the best conditions, Patchouli actually improves with age; typically, distillers suggest Patchouli has a twenty-year shelf-life. Indeed, I wasn't much of a fan of Patchouli until I encountered the intoxicating fragrance of a vintage Patchouli that was originally distilled over twenty years ago!