Tom's Blog

Tuesday, November 24, 2015

White indigo (Baptisia alba) tumbleweeds

This is the time of year when white indigo (Baptisia alba) seed stalks break off and blow away. They act like "tumbleweeds", getting blown across the prairie. The seeds of this legume are heavy, but many of them remain in their pods for long after maturity. Thus, their behavior seems to play a role in seed dispersal.

Once the stalk breaks, the seed head becomes top-heavy, ensuring that the seeds get placed near the soil where they can do the most good.

White indigo seed stalks spontaneously turn upside down when the stems break
All it takes is a strong wind to carry these seed stalks far from where they have started. It's neat to watch them rolling across the prairie.

Plants of quite a few species are dispersed as tumbleweeds. Most are found in farther west, in the Great Plains and deserts. As far as I know, white indigo is the only species of the midwestern prairies that acts as a tumbleweed.

The other species we have, cream wild indigo (Baptisia bracteata) is built closer to the ground and is not a tumbleweed.

B. alba in full bloom
White indigo is a very showy plant (C value of 8) and is highly desirable in tallgrass prairies. It prefers mesic sites, although we also have lots of it in our more open oak savannas. Fortunately, it is fairly easy to get established.

At Pleasant Valley Conservancy we have a remnant population of white indigo on the North side of Toby's Prairie. This population was in an area that just escaped the plow (in the days when Toby's Prairie was an ag field). We collected and seeds and planted them in most other areas of the Conservancy. Although it takes a few  years for them to get started, once they are going they take care of themselves.


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