Common Names hoary cress, whitetop
Flower Color White
Plant Type Herb
Hoary cress or whitetop (Cardaria draba) is native to the Balkans, Georgia, Armenia, Azerbaijan, Turkey, Israel, Syria, Iraq and Iran. Two other Cardaria species are common in the western US, lenspodded whitetop (C. Chalepensis and hairy whitetop (C. pubescens). Whitetop was introduced to the U.S. by early European explorers in North America. It has since spread throughout almost the entire country. Whitetop has spread or is spreading into many of the rangelands of Malheur and Baker Counties of Oregon. It has also been found that one time tilings of the soil will spread this noxious weed, and that it takes 3 consecutive years of tiling to destroy the root system. Whitetop emerges in early spring, then blooms and sets seed by mid-summer. Whitetop spreads by seed and vegetatively under the soil.