It was way back in the fall of 2016 that I planted Wild Senna (Senna hebecarpa) in a corner of the Sidewalk Border. I was excited about this member of the Pea Family (Fabaceae) because of its unusual flowers and foliage, because it was highly attractive to bumblebees, and because it is a host plant for Sulphur butterflies.

Wild Senna flowers

Well, over the following three years it was pretty slow to establish. By last summer it featured just a sparse handful of flowers. I was worried that its location was too shady, as Wild Senna prefers full sun. While some gardeners engage in zone denial, I have a habit of convincing myself that a given spot is really sunnier than it actually is.

In our garden, Wild Senna is a bit sprawling, but it is a substantial plant.

This year, however, Wild Senna is full of flowers. It’s grown nearly 7′ tall, though its habit is rather sprawling – perhaps it would be tighter with more sunshine? I had been thinking of transplanting it to another spot in full sun. That spot, however, is more out-of-the-way, and I think this is a plant that deserves exposure.

The foliage looks a bit tropical to my eye.

I don’t think I have ever seen it for sale in a garden center – only in specialty native plant catalogs. Even so, Wild Senna deserves to be tried in more home gardens, at least by those gardeners who are a bit adventurous.

Wild Senna flowers are unusual even for members of the Pea Family.

The flowers open from the bottom up. To me they look a bit like yellow popcorn.

Has Wild Senna been successful in your garden?

19 Comments on “Wild Senna Prospers in Part Shade”

  1. Wild Senna has come back with a vengeance in my yard and is spreading itself around as is the Tall Ironweed I planted. I don’t know if it was the cool spring or the amount of rain or what but these two have been having almost too good a time. Both are in pretty full sun.

  2. This genus is not native here, but related species used to be more popular in Southern California. Some were pruned up as small trees, either on straight single trunks, or with a few irregular trunks. There was also a Cassia that was known as a senna. I think that there are Sennas that are known as cassias too.

  3. That does look like yellow popcorn! The Garden Club of Danville, (Kentucky) maintains the herb garden at the Ephraim McDowell House. ( Ephraim McDowell, “ a founder of operative gynecology” (Britannica.com)). It was here that I first saw wild senna growing. It was located in a favorable spot and was thriving. Yours is only the second sighting I’ve had. Perhaps I should return to Danville after blooming season and gather some seed pods.

  4. I know of two natives here. Senna roemeriana, or two-leaf senna, grows smaller, in a rounded shape. Lindheimer’s, or velvet-leaf senna, also tends to clump more, although it’s described as being 3′-6′ tall. Both are lovely, and I’ve been lucky to find both growing wild. I love that the two species are named after Roemer and Lindheimer, two of our most well-known botanists.

    A side note: I was lucky enough to visit a Lindheimer exhibit in New Braunfels, and saw some of his herbarium sheets, with hand-written notes. The senna was included.

  5. It does quite well in my garden in partial sun. I have learned to deadhead it right after the flowers fade. Otherwise, if you let the pods develop and dry, you will have it everywhere. Also, don’t put the pods in your compost heap unless yours gets “hot.” I do like the look of it.

  6. Your senna looks beautiful!. I so admired the popcorn Senna ((Senna didymobotrya) that I saw in Spain that I gathered the seeds in the hope of growing them here in S.W. France. I succeeded with beautiful, healthy young plants and I was sure all would be O.K. as last winter was very mild, for us. Unfortunately, not one plant survived. I’ll just have to admire your Senna. Amelia

  7. Hello there Jason … this post made me smile because I absolutely imagined popcorn ! LOL
    I really like the structure of the foliage as well as those outstanding yellow flowers .. the pollinators must be in heaven with feeding from them.
    This zone and light value denial ? .. I am stuck in it too .. but I think I finally nailed my rodgersia .. after 3 plants ? .. it finally takes the correct course of position .. go figure ? LOL
    That size of your plant is very impressive indeed !

  8. Your Senna looks quite attractive. Shade doesn’t seem to be hurting it. Did not know there was one native to North America.

    Here non-native Senna didymobotrya has naturalized to an extent, from Los Angeles county down to San Diego. Bees like it, including bumble bees. Have not seen any interest from hummers.

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