Category: weeds...

a weed is any plant growing where it is not wanted; the category is ever-changing and the term is a relative one
A weed is a treasure, and a treasure is a weed.
With each weed you pull up, you make room for fresh grass or flowers.
plants become weeds as a function of time and place
Nature knows no difference between weeds and flowers. (M. Cooley)
What is a weed? A plant whose virtues have not yet been discovered (R.W. Emerson)
Each humblest plant, or weed, as we call it, stands there to express some thought or mood of ours; and yet how long it stands in vain!... Beauty and true wealth are always thus cheap and despised. (Henry David Thoreau)