ABSTRACT
The most hated of lawn weeds - crabgrass and dandelion - generate fanatical efforts at eradication. Dandelions and crabgrass, which are highlighted in this review, are considered to be the worst lawn weeds, and the species which are most responsible for excessive and unnecessary ecologically unsustainable practices. In this chapter, Canada thistle, the leading urban prickly plant, is examined. The C4 system is another of the weapons that makes crabgrasses possibly the world's most hated lawn weeds. Crabgrass has potential for disposal of livestock waste, as it has been demonstrated to employ manure efficiently as a fertilizer. In partial compensation for their deleterious effect on biodiversity, it may be noted that dandelions and other flowering weeds in turfgrass lawns provide significant food resources for declining pollinator populations in urbanized landscapes. Japanese knotweed was once considered to be desirable for planting as an ornamental, forage, and for erosion control, but its ability to escape cultivation precludes it for these purposes.
