Accession Count: 3
Common Name:
triangle leaf bursage, burro-weed
Family Name:
Asteraceae
Botanical Name:
Ambrosia deltoidea
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics:
Triangle bur ragweed is a relatively short-lived (<50yrs), drought-deciduous shrub that grows up to 0.5m (1.65ft) with many slender but brittle branches forming a compact, rounded form (1, 2). As branches mature, they become more reddish-brown and later die back allowing for dead branches to be naturally and easily shed due to wind and rain and the inherently brittle nature of the stems (1, 2). Stems and leaves have a tomentose covering and produce fragrant resin (1, 2). Leaves are 1.5-2.0cm (0.6-0.8in) long, greenish-grey on top and gray-white on the bottom, become glabrous with age and are borne on short petioles (1, 2). The leaf margin is finely toothed(2). The plant is dioecious with staminate flowers borne on the stem termini and pistillate flowers growing in a cluster below the terminal male spikes or on the lateral branches (1, 2). Flowers are dull yellow-green and appear in April or May and persist through November or December (1). The fruit is a globe-shaped, spiny achene (1) which contains fusiform burs that facilitate seed dispersal (2).
Compound:
amb del
Geographic Origin:
Southwest US
Ecozone Origin:
Nearctic
Biome Origin:
Desert
Natural History:
Triangle bur ragweed is a relatively short-lived (<50yrs), drought-deciduous shrub that grows up to 0.5m (1.65ft) with many slender but brittle branches forming a compact, rounded form (1, 2). As branches mature, they become more reddish-brown and later die back allowing for dead branches to be naturally and easily shed due to wind and rain and the inherently brittle nature of the stems (1, 2). Stems and leaves have a tomentose covering and produce fragrant resin (1, 2). Leaves are 1.5-2.0cm (0.6-0.8in) long, greenish-grey on top and gray-white on the bottom, become glabrous with age and are borne on short petioles (1, 2). The leaf margin is finely toothed(2). The plant is dioecious with staminate flowers borne on the stem termini and pistillate flowers growing in a cluster below the terminal male spikes or on the lateral branches (1, 2). Flowers are dull yellow-green and appear in April or May and persist through November or December (1). The fruit is a globe-shaped, spiny achene (1) which contains fusiform burs that facilitate seed dispersal (2).
Cultivation Notes:
Triangle bur ragweed reproduces sexually, and produces a large quantity of seed (2). The ubiquity of seed production and the spiny burs improve the odds of seedling development and establishment (2). The plant can also be propagated asexually from woody cuttings treated with auxin (2).
Ethnobotany:
Triangle leaf bursage has many roles in supporting ecosystems. They serve as nurse plants for saguaro, as pollinators for small butterflies, bees and insects, and produce seed that feeds birds and small mammals (2). It may also be used to stabilize soil, restore disturbed sites and reduce erosion (2). While the male flower does produce a pollen that may trigger allergies (1), it is also an attractive scrub to be retained or cultivated during urban development (2).
Height:
0 - 5 feet
Width:
0 - 5 feet
Growth Rate:
Fast Growing
Grow Season:
Spring
Flower Season:
ForeSummer
Color:
Yellow
Function:
Habitat
Spread:
Non-spreading
Allergen:
Allergenic
Invasive:
Benign
Toxicity:
Hardy:
Hardy
Water Use:
Low water Use
