Weeds in flowers' clothing: Garden plants that wreak havoc

"For most gardeners, the rearing of a dandelion head evokes an almost visceral response.

Weeds such as buttercup, thistle and bindweed are considered intolerable, particularly when they edge their way into manicured turf and neatly tended beds. And yet, many gardeners overlook - even welcome - the most sinister weeds: invasive species that masquerade as harmless ornamental beauties."