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Wednesday - March 09, 2011

From: Granbury, TX
Region: Southwest
Topic: Poisonous Plants
Title: Toxicity of Texas Mountain Laurel seeds to livestock and dogs?
Answered by: Jimmy Mills

QUESTION:

Are the seeds of the Texas Mountain Laurel poisonous to livestock or dogs? Thanks

ANSWER:

Texas Mountain Laurel Sophora secundiflora (Texas mountain laurel) is a popular native evergreen because of its dark green foliage and spectacular purple flowers, but it is generally considered to be toxic, particularly the brilliant red seeds.

One of the sources that we go to when asked about toxic plants is Toxic Plants of Texas, and it confirms the toxicity of Texas Mountain Laurel. The toxic agent is cytisine, a quinolizidine alkaloid, which is found in the leaves and the seeds. Livestock are poisoned when they ingest the leaves, however the leaves are thought to be unpalatable and are avoided when other food is a vailable. The seeds have a higher concentration of the cytisine, but unless the seeds are broken through mastication, they can pass through the digestive tract with little effect.

Cytisine is also toxic to humans, and children are attracted to the red seed.