Native Plants

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Saturday - April 14, 2007

From: brenham, TX
Region: Southwest
Topic: Wildflowers
Title: More on bluebonnets
Answered by: Nan Hampton

QUESTION:

Do bluebonnets, being a legume, contribute anything beneficial to the soil?

ANSWER:

Lupinus texensis (Texas bluebonnet), like most of the members of the pea family (Family Fabaceae), fixes nitrogen, i.e., transforms atmospheric nitrogen into a form that can be used by the plants for growth. They don't do this alone, however. Nitrogen fixation happens when the plants form a symbiotic relationship with soil bacteria called rhizobia. Not only is this beneficial to the bluebonnet (or other nitrogen-fixing plant) but it also benefits non-nitrogen-fixing plants. When the bluebonnet plant dies, its decomposition products, including nitrogen, are released into the soil to be taken up by other plants.