a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests

perennial often aromatic and sometimes mat-forming herbs of north temperate regions: yarrow; milfoil

ubiquitous strong-scented mat-forming Eurasian herb of wasteland, hedgerow or pasture having narrow serrate leaves and small usually white florets; widely naturalized in North America

Eurasian herb having loose heads of button-shaped white flowers and long grey-green leaves that cause sneezing when powdered

perennial often aromatic and sometimes mat-forming herbs of north temperate regions: yarrow; milfoil