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Description
The larkspurs are perennial herbs growing 1 to 3 feet tall.
The leaves are deeply divided from a single point into numerous
fine, narrow segments and are usually confined to the bottom
half of the plant. Showy, light blue, blue, purple or white
flowers are arranged along the top of the erect stalk. The
distinguishing characteristic of the flower is the prominen
tbackward trailing “spur.”
Distribution and habitat
One or more species of Delphinium may be found in open pastures,
hillsides or valleys of all vegetational areas of Texas.
Regions: 1, 2,
3, 4,
5, 6,
7, 8,
9, 10.
Toxic agent
More than 40 different diter-penoid alkaloids have been identified
from Delphinium spp., but most of these are from the tall
larkspurs of the mountains in the western United States. Toxicity
varies greatly among species, as does the concentration of
toxins. Usually, alkaloid concentrations are highest in the
spring after flowering and gradually decrease as the plant
matures. All parts of the plant should be considered toxic.
All species of livestock may be affected, though cattle are
the most susceptible. Texas larkspur species are small plants
with scant foliage, and poisoning is uncommon. Despite this,
all larkspurs should be considered to be potentially toxic.
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Livestock signs
Larkspur primarily affects the neuromuscular system and consequent
signs of poisoning include:
Integrated management strategies
Larkspur poses the greatest risk to livestock in the spring.
Losses in heavily infested areas may be reduced by keeping
cattle out of pastures until after the plants have
flowered and gone to seed, or by grazing sheep, which are
more resistant, before cattle. Because treating larkspur
with some herbicides increases its palatability, do not
use treated pastures for grazing until the affected plants
are dead..
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