Common Ragweed (also known as Annual Ragweed, Bitterweed, and Roman Wormwood)
Kingdom: Plantae, Division: Tracheophyta, Class: Magnoliopsida, Order: Asterales, Family: Asteraceae, Genus: Ambrosia, Species: Ambrosia artemisiifolia · Asteraceae (Aster, Daisy, or Sunflower family) · Simple (lower leaves can be deeply lobed or compound-like), deciduous annual
Species
Ambrosia artemisiifolia
Leaf Type
Simple (lower leaves can be deeply lobed or compound-like), deciduous annual
Family
Asteraceae (Aster, Daisy, or Sunflower family)
Shape
Lanceolate to ovate, deeply pinnately lobed or dissected
Size
Approximately 2-4 inches long and 1-2 inches wide, typical for mature specimens
Margin
Coarsely toothed to lobed
Arrangement
Opposite near the base and becoming alternate higher up on the stem
Rarity
Very Common, often considered a widespread agricultural and urban weed
Color & Pattern
Dull green to grayish-green on both upper and lower surfaces, lighter beneath with fine hairs
Venation Pattern
Pinnate venation with a prominent pale midrib
Texture & Surface
Slightly rough or hairy (pubescent) due to fine trichomes
Description
Common Ragweed is an herbaceous annual plant that typically grows from 1 to 4 feet tall. It features branching stems covered in fine hairs and produces inconspicuous greenish flowers arranged in terminal spike-like racemes. The male flowers release copious amounts of pollen into the wind, making it notorious among allergy sufferers.
Key Features
Deeply divided, fern-like or lobed leaves, hairy stems, and distinctive long spikes of small, greenish male flower buds hanging downward
Habitat
Disturbed soils, agricultural fields, roadsides, waste areas, and vacant lots in full sun
Geographic Range
Native to North America, now widely naturalized across Europe, Asia, and other parts of the world
Condition Notes
The specimen appears healthy with minor insect feeding damage on the lower leaf margins, typical for summer foliage in the wild
Interesting Facts
A single ragweed plant can produce up to a billion grains of pollen per season, which can travel hundreds of miles on the wind, making it the primary trigger for autumn hay fever
Medicinal & Uses
Historically used in traditional Native American herbal medicine for various ailments such as fevers and skin irritations, though modern uses are virtually nonexistent due to its extreme allergenic properties
Ecological Role
Provides food for various granivorous birds and small mammals, though it is primarily recognized as a prolific weed species rather than a conservation priority
Similar Species
Giant Ragweed (Ambrosia trifida), which has much larger, typically three-lobed leaves, and various wormwoods (Artemisia species) which share deeply dissected foliage
Foraging Tips
Look for disturbed ground along roadsides, railway tracks, and agricultural edges during summer and early autumn when the flower spikes are fully developed
Toxicity Warning
Non-toxic to ingest, but the pollen is a potent allergen causing severe hay fever, rhinitis, and asthma symptoms in sensitive individuals