Broad-leafed Milkweed, Common Milkweed
Asclepias latifolia
Description
More than 30 species of milkweeds have been recorded in Texas. Broad-leafed milkweed is noted for its robust nature and leaf size. A perennial, this plant has stout simple stems and four or more pairs of large thick leaves no more than twice as long as they are wide.
The flowers are greenish to white, giving rise to two to four smooth pods about 2 to 3 inches long from July to October.
Habitat
Broad-leafed milkweed is most common along trails and roadsides, less so in pastures. As with many weeds of low palatability, this species increases in heavily grazed pastures. It is frequent to abundant over much of the Trans-Pecos, the Plains and the central and western Edwards Plateau of Texas. It is found from Nebraska to Utah and west to Arizona.
Toxic Agent
This plant poisons cattle and goats, but more often sheep. The toxic agents are cardiac glycosides.
To be poisoned, cattle can eat as little as 1.0 percent of their body weight in broad-leafed milkweed; amounts as low as 0.15 percent have poisoned sheep and goats. Broad-leafed milkweed is toxic in all growth stages, but is most toxic when immature. Cattle can generally graze frost-killed plants and not be poisoned.
Signs of Livestock Ingestion
The signs produced by most species of Asclepias differ only in degree.
They include: First, profound depression, weakness and staggering; Collapse, followed by frequent, intermittent muscular tremors; Labored respiration, elevated temperature and pupil dilation; Death, after a comatose period of variable duration.
Signs appear within a few hours of ingestion of a toxic dose, and death follows within a few days in most fatal cases.
Management Strategies
The best way to prevent losses from broad-leafed milkweed is to maintain good range condition.
Removing plants along trails and in holding traps may prevent many losses, especially when hungry livestock are being trailed.
Avoid placing many animals where infestations are severe and forage is limited. Do not feed hay contaminated with milkweeds. Although no medicinal treatment is specified, sedatives, laxatives and intravenous fluids may help.
Images
Plant Characteristics
Flower Color: White
Seed Type: Bean/Pod
Duration: Perennial
Stem Texture: Hairless/Smooth
Growth Habit: Forbs/Broadleaf
Leaf Shape
: Simple with Pinnate or Parallel Venation
Season: Warm
Distribution
: 07 - Edwards Plateau, 08 - Rolling Plains, 09 - High Plains, 10 - Trans-Pecos
Distributions
Distribution refers to the ecological region in Texas that a plant has been found. You can also view a clickable map.
Book: Toxic Plants of Texas (B-6105)
Collection: Toxics, Wild Flowers
Livestock Affected: Cattle, Goats, Horses, Sheep
Livestock Signs: Abnormal Heartbeat, Collapse, Coma, Convulsions, Depression/ Weakness, Dilated Pupils, Excess Salivation, Incoordination, Irregular Breathing
