its just an idea, something to consider..

UV B and UV C are the worst rays.. A is the least of any life form's troubles..

Essential oils in the plant?

Essential oils are thought to be excretory products formed during the metabolism of substances vital to the life of the plant. They are said to occur when chlorophyll from the plantsā?? leaves come into contact with photons (UV and IR rays) from the sun.

Their odour properties may have a specific relationship with insects and of animals, but not much to do with the life of the plant itself.

In the flower, essential oils occur in the internal surface of the epidermis of the cells in special secretory glands and are store in the plant in minute sacs.
the black light blocks UV-C and UV-B rays so damage to the plant is virtually impossible according to what i've read. It does allow UV-A and IR rays to pass through, which are mentioned in this article..