Garden Talk

with Rebecca Jordi


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Q:  What is this large wildflower growing in my yard? 

Showy Rattlebox, Crotalaria spectabilis

Showy Rattlebox,
Crotalaria spectabilis

 A:  Thanks for bringing in a specimen of this large plant. It most likely belongs to the genus, Crotalaria. There are approximately 600 species of Crotalaria worldwide. I believe your plant is a Showy rattlebox. If it is Showy rattlebox, Crotalaria spectabilis, then it is native to southern Asia but now can be found worldwide. In the United States it occurs from Missouri to Virginia south to Florida and Texas. Showy rattlebox can reach heights up to six feet with bright showy pea-like flowers up to an inch wide. These flowers will bloom in large clusters along a tall stalk which is where it gets the name “showy.” The rattlebox name comes from the sound the seed makes in the pod once it has become dry and mature. This annual legume is native to Indomalaysia and was introduced to the United States as a soil building cover crop on sandy soils. Showy rattlebox can be poisonous to livestock, particularly when seeds are consumed. Like other Crotalaria species, showy rattlebox contains pyrrolizidine alkaloids, which is present in greatest quantity in the seeds. All livestock including poultry are subject to poisoning. Symptoms include photosensitization and liver disease within a few days to 6 months following consumption. Showy rattlebox has been a problem for farmers. Since it is an annual legume, it produces large numbers of seed as this is its only means of propagation. Showy rattlebox prefers open and disturbed sites generally because these sites tend to be poor nutritionally.

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