Christian folklore, traditions and legends concerning plants?

With the present situation of the coronavirus affecting many of us, and many sensing the need to be able to get outside and do something, if one’s local restrictions permit it, I would like be able to go out “in the wild” and be able to identify various plants that are either related to Christian folklore and/or Christian symbolisms of some sort. What got my interest in this subject was when I was doing research on Christian traditions with foodstuffs from around the world. For example, some time ago I came across an interesting tidbit (at least for me) about Ostrich ferns also known as the fiddlehead fern: > Fiddleheads or fiddlehead greens are the furled fronds of a young fern, harvested for use as a vegetable. > > The fiddlehead resembles the curled ornamentation (called a scroll) on the end of a stringed instrument, such as a violin. **It is also called a crozier, after the curved staff used by bishops, which has its origins in the shepherd's crook **. - Fiddlehead fern (Wikipedia) Another more common example can be found in the plant known as St. John’s Wort : > The common name ***"St John's wort"*** may refer to any species of the genus Hypericum. Therefore, Hypericum perforatum is sometimes called "common St John's wort" or "perforate St John's wort" to differentiate it. > > **St John's wort is named as such because it commonly flowers, blossoms and is harvested at the time of the summer solstice in late June, around St John's Feast Day on 24 June.** *The herb would be hung on house and stall doors on St John's Feast day to ward off evil spirits and to safeguard against harm and sickness to man and live-stock.* The genus name Hypericum is possibly derived from the Greek words hyper and eikon, in reference to the tradition of hanging plants over religious icons in the home during St John's Day. Thus my question is as follows: **Does there exist a good resource material source book that deals with such plants involving Christian folklore, legends and traditions?** Symbolism is likewise included. If no book truly is out there, I would then prefer an online source of information. For what it is worth, I am not limiting this question to any specific Christian tradition. Any sources in other languages or non English countries are also welcome.