Thermopsis, seed pods

Thermopsis villosa, aka Blue Ridge Buckbean, Carolina lupine, Aaron’s rod, Bush pea, and other names, all for virtually the same charismatic plant.

06012018 thermopsis seed pod
June 1, 2018.

Previous posts:

Mega thermopsis update

It’s that time of year. The thermopsis (Thermopsis villosa, aka Blue Ridge Buckbean, Carolina lupine, Aaron’s Rod) are nearing the end of their bloom, and (hopefully) the pods will follow.

This is a thermopsis summer! This has been their most prolific year. I mulched a few with compost, hoping it will encourage them to set many seeds.

Previously, I posted a photo of the thermopsis just as the raceme is emerging from the apical meristem.

In the beginning…

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May 17.
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May 17. The blooms are peeping out of the lowest buds, nearly ready to see the light of day. (I’m not sure why this photo and others are so washed out)
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May 20.
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May 21. What a difference a day makes. A heath or some other aster (Symphyotrichum spp.) has snuck into this photo (right).
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May 21.
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May 21. Three-year chestnut hybrid (Castanea dentata x) in the foreground, flowering sorrel (Rumex acetosa) in the back left.

The following photos were taken about five days later.

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May 27. It may be evident that the lower blooms are fading away, while the top-most buds have not yet bloomed.

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Legumes in flower

You will notice that the Astragalus canadensis (Canadian milkvetch) is conspicuously absent from this post on native legumes. Fear not, I am gearing up for a post all of their own, hopefully soon. Some did not make the winter, but most braved the brutal cold and lived to tell the tale. But that’s a story for another day.

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Thermopsis villosa. Blue Ridge buckbean, Carolina lupine, Aaron’s rod. Looking closely, the bud can be seen emerging from the tip of the stalk. This two-year old plant had at last ten budding stalks. Note the three-fingered leaf-hand to the left (and the smaller one to the right, alternate), extended as though to welcome the flower bud into the light of day.  May 8, 2018
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Amorpha fruticosa. False indigo bush. The leaves of this legume are less clover-like (or trifoliate), and more like the black locust (odd-pinnately compound). May 8, 2018
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Amorpha fruticosa. Flowers from the growing tip of the woody stalk. May 8, 2018.
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Just a few days later, Amorpha fruticosa in flower. Appreciated by some species of bumble bee. the pollen-bearing stamens, yellow, emerge from deep violet flowers, giving each inflorescence an iridescent sheen. May 11, 2018.


Thermopsis villosa syn caroliniana (Blue-Ridge Buckbean, Carolina golden banner, Carolina bush pea, Aaron’s rod). Seeds from Prairie Moon had a very nice germination rate (they arrive scarified). They came with a Thermopsis inoculum (which is the same as for Baptisia inoculum, perhaps indicating their genetic proximity). Thirty day cold-moist stratification. Scarify with sandpaper or by pouring boiling water and let sit overnight.

This plant brings happiness to my heart.

Our Thermopsis flowered for the first time in the garden this Spring. I have saved seeds, and am nervous because that means I (may) need to scarify them myself. The Prairie Moon accession, I sowed in flats in February, and was pleased to see them germinate in March or so. After that, I ran out of time, so they were largely on their own until yesterday, October 28. Of the ones that made it the first month, there was zero loss.

I may go ahead and sow the collected seeds (“Megadiverse” accession? -not yet) now, to see if I can circumvent scarification.

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The distinct leaflets-of-three can be seen towards the top left. These will be interplanted in a perennial bed with Scrophularia marilandica (figwort) and Scutellaria lateriflora (skullcap).
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Here can be seen the delicate pink nodules, which host an invasive symbiotic rhizobium that acts to fix nitrogen from the atmosphere and convert it to a form that the plant is able to take in.
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This will be next year’s growth.


Chapin (2009).

thermopsis distribution

The above map from Weakley (2015) indicates that Thermopsis is endemic to a small portion of Appalachia. It’s southerly reach indicates to me that it may thrive in our climate zone, 7A. A goal of mine (really a quest) is to locate a naturally-occurring population of this plant in Rockingham County, thus indicating that it’s reach is a bit more easterly than determined.
Source:  Kartesz, J.T., The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. ( Chapel Hill, N.C