Beach ragweed, Coastal ragweed
Ambrosia hispida

Landscape Uses:

An accent groundcover in open coastal locations.

Ecological Restoration Notes:

Rather sporadic along the South Florida coast. Perhaps never common, but its numbers may have been reduced by coastal development and erosion.
Grown by one or two native plant nurseries in South Florida. Available in Sanibel at the Sanibel Captiva Conservation Foundation (239-472-2329).
Small spreading herb.
Typically 1-3 feet in height but sometimes climbing into other vegetation. Spreading and forming large mats.
Growth Rate:
Moderate to fast.
Monroe County Keys and Miami-Dade County north along the coasts to Brevard and Lee counties; West Indies, southern Mexico and Central America. Rather rare and sporadic throughout its range in South Florida.
Beach dunes and coastal strand.
Moist, well-drained sandy soils, without humus.
Nutritional Requirements:
Low; it grows in nutrient poor soils.
Salt Water Tolerance:
Low; does not tolerate long-term flooding by salt or brackish water.
Salt Wind Tolerance:
Secondary line; tolerates significant salt wind without injury, but usually is somewhat protected.
Drought Tolerance:
High; does not require any supplemental water once established.
Light Requirements:
Full sun.
Flower Color:
Flower Characteristics:
Flowering Season:
All year; peak in summer.
Inconspicuous achene with 1-5 conic spines. All year.
Wildlife and Ecology:
The flowers are pollinated by wind.
Horticultural Notes:
Can be grown from cuttings. Newly planted patches may spread rapidly, then die back after 2-3 years.
An excellent groundcover in coastal areas with high light.

Roger L. Hammer
Michelle Hayden
In habitat, Eleuthera, Bahamas, 2013
Cara Abbott, 2023.