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Description
Snow-on-the-mountain and snow-on-the-prairie are annual herbs
in the spurge family. They generally grow to 1 to 3 feet tall.
The flowering stems have a peculiar construction: a whorl
of four to five petal-like members, usually yellow-green,
surrounding a cluster of male flowers, each consisting of
a single stamen. E. marginata leaves are long, oval and nearly
hairless and come to a blunt point; the upper leaves usually
have distinct white margins. E. bicolor leaves are similar
but narrower.
Distribution and habitat
Snow-on-the-mountain is locally abundant in Central Texas.
It is somewhat uncommon in the Rio Grande Plains and Trans-Pecos
regions. It also grows north to Montana and Minnesota and
south to Mexico. It is found most often in tight clayey soils
of swales
and meadows and in dry stream beds. Populations can vary greatly
from year to year. Snow-on-the-prairie is commonly found in
the eastern third of Texas.
Regions for E. bicolor: 1,
2, 3,
4; for
E. marginata: 5,
6, 7,
8, 9,
10
Toxic agent
The white sap of these plants has long been used to blister
the skin or as an intestinal purgative. In most cases, livestock
are poisoned by an acrid principle that severely irritates
the mouth and gastrointestinal tract. This plant rarely causes
death. Experimental feedings of this plant in Texas have shown
that 100 ounces produces severe scours and weight loss in
cattle, the latter persisting for several months.
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Livestock signs
Primary signs include:
- Severe irritation of mouth and gastrointestinal
tract
- Diarrhea
Integrated management strategies
Most species of spurge can be grazed to a limited degree
without problems. Their bitter white juice apparently makes
most species unpalatable. Administer intestinal astringents
if needed to relieve diarrhea and intestinal wall irritation.
Although most broadleaf herbicides control the plant easily,
it is generally uneconomical to control as a primary target
species. Proper mineral supplementation, especially of phosphorus,
reduces livestock losses to the plant.
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