Hoping someone can answer this...based on their experience.

Well, the blooms are not necessary to attract butterflies, although they help. I have never tried to take cuttings from the ones that I have, but I imagine that it should be possible. What you might try is to prune the top to see if that helps to encourage it to branch out. It should. Perhaps take some cuttings from what you cut off?

I really like this plant, but mine are now being overgrown by the Hamelia Patens. I have a Cassia bush/tree that has grown something like 30 feet up into another tree and the sulfurs use it a lot, so I don't need more cassias.

Lets us know what you do and how it goes.

Apparently it knew I was thinking of cutting the top off and within the past few weeks has put out all sorts of side growth. I guess I just wasn't patient enough!

You will need to figure out how to protect it from the cold. I guess that won't be easy with it being in a whiskey barrel. Maybe take some cuttings for insurance? I have had several Cassias die on me because of freezes.

I have a large greenhouse and will just move it in as I did last year. I also have a semi enclosed back porch with heat lamps and can always use that space as well...probably a 9' ceiling there (higher than the greenhouse).

I'm not sure how to prune your cassia because I believe it's tropical and I only have experience growing deciduous species.The two I've grown,hebacarpa and maralindica grow about 5 feet high and completely die all the way to the ground in winter.There are some butterfly species like blues whose cats feed and overwinter inside their seedpods,so I leave the pods on until late spring. I saw a pic of the one you have and the flower spikes are quite beautiful. I'm sure if you search the web you can eventually find information on how to prune and care for your species.Annie's Annuals was selling your plant and I'm pretty sure they would be happy to share that info with you if you inquired. I had never heard of your species before until now,nor was I aware there were tropical forms. I can't wait to read about them.Best of luck with your pruning.

I never found anything re: pruning (I searched the web prior to posting here), but it must have known that I was thinking about it because it sent up all sorts of new side growth. The plant is now well over 9' tall and nearly impossible to get into/out of the greenhouse, so it will get lopped at some point. BUT, there is lots of side growth and I may attempt to start a new plant from the top as it is green vs hardwood.

THANKS!

I rooted many cuttings of a different Senna.

Regarding its heigt and ceiling heights : It need not be vertical. Nor straight.
With that in mind, you will think of a simple way to accomodate it.