The Friar knows human character as well as plants
Friar Lawrence ends up playing a key part in the tragic love story of Romeo of Juliet, despite being a relatively minor character. Although Catholics were not generally looked upon with a friendly eye in the Elizabethan era, Shakespeare generally describes the Friar in a respectful way.
He appears to be a kind, sensible man who is a good judge of human character. For instance, he explains to Romeo that his feelings for Rosaline were not real love and that she knew it: “O, she knew well/ Thy love did read by rote that could not spell.” (2.3.88-89)
When we first meet Friar Lawrence it is in Act 2, Scene 3 where he is gathering herbs. He delivers a soliloquy on the healing or fatal power of plants:
For nought so vile that on the earth doth live
But to the earth some special good doth give.
Nor aught so ...