Thursday, October 31, 2013

My favorite plant this week: Senna (Cassia) bicapsularis

I looked around for a scary plant I could feature in this week's favorite post in a toast to Halloween but I couldn't come up with anything truly sinister (unless you count the mimosa tree that's on a march toward world domination with its relentless self-seeding but I'm tired of giving it attention it doesn't deserve).  Instead, I picked Senna (Cassia) bicapsularis  'Worley's Butter Cream' as my favorite because it finally sprung into bloom just when I'd about given up hope that it would.  Last year, it began blooming in late summer.  I thought that the failure to bloom this September might be due to getting too little water this year.  It was a very dry year and the Senna is planted at the top of the stairs leading down the slope at the back of our property, an area that gets watered haphazardly by hand.  However, in examining on-line sources regarding this tropical shrub, I discovered that it commonly blooms in late fall or winter.  In fact, some of its common names are Christmas Senna and Winter Senna.  So apparently it actually bloomed very early last year and it's blooming somewhat early this year.

It isn't a particularly easy plant to photograph, though.  Its position along the fence between us and our neighbor at the top of the slope stairway makes it difficult to find a good vantage point from which to take a picture.  It has also gotten quite tall - over 7 feet tall at my rough estimate.  It can grow 8-10 feet tall and 6-8 feet wide so its current placement isn't optimal.  I may try pruning it to a more manageable size following the current bloom cycle.

Picture taken from the far end of the dry garden,  In a happy coincidence, the neighbor's Brugmansia, sporting similar floral color, is blooming again on the other side of the fence.

Picture taken from one of the stair steps below the Senna bicapsularis


Taxonomists have yet to agree on whether this shrub should be considered part of the Cassia or Senna genus.  There also seems to be some confusion as to whether or not it should be classified as an invasive plant.  One source holds that its invasive label is undeserved and attributable to confusion between this plant and Senna pendula var. glabrata.  I can only say that, after 2 years in my garden, I've seen no sign whatsoever of rampant self-seeding.

This evergreen plant is native to the northern part of South America and the West Indies.  The bright yellow flowers attract butterflies and bees.  It provides larval food for the Sulphur butterfly.

The flower buds look like small yellow marbles




It prefers regular water, although in my experience it can tolerate a little drought.  Reportedly, it can be grown in USDA zone 8 as a perennial.  It is winter hardy in USDA zones 9-11.  Senna (Cassia) bicapsularis is my contribution to Loree's favorite plants meme at danger garden.  You can check here for her choices for plants of the week.

Oh, and from my home to yours, Happy Halloween!


9 comments:

  1. Beautiful plant choice, I think I saw this plant on a garden tour recently and we were all interested in knowing what it was. The owner called it Cassia senna and I had planned to look it up soon.

    The flowers are gorgeous!

    Happy Halloween!

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    1. I hope you had a great Halloween too, Shirley.

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  2. Love the last photo! :) Cassia - or senna - is quite pretty, and I love plants that bloom when others don't (late autumn or winter). I'm in zone 8, but I may have to give this one a try.

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    1. Next year I think I'll have to dress up for my Halloween picture!

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  3. Happy Halloween to you too! What interesting flower parts the Senna (Cassia) flower has, with those two long curving stamens.

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    1. It is an unusual flower, Alison. I like the round buds too.

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  4. I love the photo with the big banana leaves behind your Senna (Cassia), the contrast sets it off nicely. Of course the leaves on your fav are pretty cool too, almost like a cotinus. Are the flowers fragrant?

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    1. Sadly, no, the flowers don't have a trace of scent that I can detect. The leaves fold closed in the evening, which I should have mentioned.

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  5. Wow, the leaves and blooms on this are so cool! I can see why this would be your favorite.

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