Birdsfoot Trefoil

 

There is a big patch of this weed in the yarrow patch.

Birdsfoot trefoil, a native to Europe and Asia, is a low-growing perennial broadleaf weed that is often found in low fertility soils. It is drought and salt tolerant. It germinates from seed mainly in the spring and quickly spreads into large colonies by developing stolons and rhizomes during the fall.