redroot

1. An eastern North American bog plant (Lachnanthes caroliana) having red roots and woolly yellow flowers.
2. A coarse cosmopolitan weed (Amaranthus retroflexus) having hairy leaves and stout terminal panicles with dense lateral spikes of green flowers.
3. See ceanothus.

The noun has one meaning:

Meaning #1: perennial woodland native of North America having a red root and red sap and bearing a solitary lobed leave and white flower in early spring and having acrid emetic properties; rootstock used as a stimulant and expectorant
  Synonyms: bloodroot, puccoon, tetterwort, Sanguinaria canadensis