Bauhinia monandra

[mnorell]

Bauhinia monandra is easily my favorite of its genus. While living in Honolulu many years ago I became enamored of this tree, and I later attempted to grow it in Los Angeles. Alas, I could never get it to survive, let alone flower, in the relatively cool UC/Sunset "zone 23" climate of the Hollywood/Los Feliz area; and I know others on this forum have discussed their disappointments with this one in SoCal. I have been experimenting with it the last few years here in the Palm Springs area, have lost a couple and in both cases had middling results until they died...but last year I planted three small seedlings in a coveted winter suntrap and where the young plants can be under the leading edge of a bit of south-facing canopy. Lo and behold all three survived last winter although two have stayed rather small and have yet to flower. The one in the most perfect position, however, grew well last season and got through the winter in excellent condition, and started back into growth in May, flowered around Memorial Day into June, then took a break for July/August and started up again at the end of August and is still blooming. To me this is a testament to the old adage of "try, try again" before giving up. (I have done the same with the oft-failing Cordia sebestena and finally have a beautiful specimen thriving in the same suntrap area as the Bauhinia monandra.)

I have noticed, however, that the coloration of this species' flowers seems very dependent on temperature. This year has featured the hottest stretch of weather in the 100+ years of record-keeping here, with extreme heat from the beginning of June until about ten days ago, topping out at 124F with almost constant 110s and several days hitting the 120s. And with only two one-week "breaks"--if you could call them that--from the worst of the heat. I noticed that the flowers were significantly paler than those I had experienced previously, and at one point they were almost white with only the flag-petal retaining its typical deep magenta pattern. However, the newest flowers, after just a week or two of highs only in the low 100s and now upper 80s/low 90s, have significantly deepened to the color-scheme I think of as "normal."  (And note that the lighter color is not from sun-bleaching, as they were protected from harsh sun under the filtered canopy of Caesalpinia pulcherrima and a nearby Hibiscus tiliaceus.)

Has anyone else here been able to successfully grow and flower this species in SoCal, either coastally or in the inland valleys or low desert? And, if so, have you also noticed this coloration issue dependent on weather/temperature conditions? I have also noticed this with my Antigonon leptopus vine, which was a very pallid pink over the summer and suddenly has also deepened into a deep coral-pink color. I know that Plumeria are notorious for changing color based on temperature and sunlight (i.e., whether grown in the fog-belt, inland valleys or deserts), but wasn't aware this was an issue with something like Bauhinia.  I did a quick search online and found some studies that showed some other flowers had a reduction in specific anthocyanins in flower-petals under heat, so I expect this is what's going on. Perhaps it is just the compound(s) involved in the pale/medium pink component, since no other colors seem affected, particularly the dark pink/magenta on the same flower; nor on something like my Mussaenda 'Doña Luz,' which retained its deep-colored bracts all summer.

Below are some of the color variations I've noticed this year on my most happily placed specimen, from "getting hot" (June) through "super hot" (Aug-Sep) to today, under more moderately warm conditions.

1 June 2024:

29 Aug 2024:

20 Sep 2024:

18 Oct 2024:

 

 

[Marie Nock]

Here's my tree in Miami.  It's in full sun and is a joy all Spring, Summer and Fall.

 

 

[mnorell]

4 hours ago, Marie Nock said:

Here's my tree in Miami.  It's in full sun and is a joy all Spring, Summer and Fall.

 

 

That's beautiful, Marie. I have always wondered why this tree is so uncommon in Miami/SoFla landscapes and nurseries. It has all the qualities of a perfect flowering tree for a typical suburban or even semi-urban home/courtyard...precocious for much of the year and arresting in its overall coloration and also color-patterns that invite close examination; blooms very young from seed, often at two feet; not as large as the more common Bauhinias, and it can be maintained at virtually any size, kept in a container or in the ground; and just in general doesn't complain much (although I seem to remember a bit of passing chlorosis on mine in the Keys on the oolitic limestone there). I've discussed this with Jessica Freund (TFTS and Freund Flowering Trees) over the years, as she is also a proponent of this species and I think equally mystified by its rarity in the trade. It's not like it hasn't been around in cultivation for a very, very long time. Perhaps people just get wowed with Bauhinia x Blakeana and look past the other contenders in the genus, it really seems odd to me. Its biggest problem is just its hatred of long, cool winters and thus apparently untenable as a landscape subject in all but the hottest areas of SoCal. And even there, its manageability and blooming behavior makes it a great winter-greenhouse/summer-display plant in a container. But in Hawai'i and Florida, it's a real winner in my own opinion and should be used much more often.

[Cindy Adair]

This is a beauty that grows well in Puerto Rico.
 

In fact there are some who consider it invasive due to seedling spread. 
 

I had one on the street outside my old farm, but not sure if it is still there after several hurricanes. 
 

This genus seems fragile during hurricanes with broken branches, but grows back quickly too.

 

Perhaps pre hurricane trimming would be best.

Not sure if subject to wind damage in  S Cal?

[mnorell]

1 hour ago, Cindy Adair said:

This is a beauty that grows well in Puerto Rico.
 

In fact there are some who consider it invasive due to seedling spread. 
 

I had one on the street outside my old farm, but not sure if it is still there after several hurricanes. 
 

This genus seems fragile during hurricanes with broken branches, but grows back quickly too.

 

Perhaps pre hurricane trimming would be best.

Not sure if subject to wind damage in  S Cal?

Cindy, I think you are very correct in that the problem is a propensity in the genus toward spaghetti branching and a congested crown. The northern (I-10) corridor of the Palm Springs area is almost constantly windy, though the cities from Palm Springs southeastward are largely protected by the Santa Rosa and San Jacinto mountains and their alluvial "coves." But even with our "only occasional" blasts of seemingly hurricane-strength wind events, I have worked very hard to keep the crown of our large Hong Kong Orchid Tree open for the passage of wind. Otherwise they are just a mess of internal crossing branches and an indistinguishable mass of foliage, and the wind can easily break up a solid crown like that. B. monandra is a smaller tree generally so probably if not out in the open wouldn't suffer to the same degree, but you bring up a good point as it's something that is helpful to be mindful of in a variety of situations and climates.

I think that all of us who have gone through the devastation of hurricanes (we got stomped on by Irma in the Lower Keys, and you by both Irma and Maria in quick succession in P.R.) got a very quick and brutal education on what to plant, where to place, how to prune, how to build structures, etc. We all graduated from that academy with a very wary and critical eye!

[metalfan]

I haven;t been able to find an actual rooted growing tree. I've tried to grow it from seeds unsuccessfully. All of ya'll look fabulous!

[mnorell]

6 hours ago, metalfan said:

I haven;t been able to find an actual rooted growing tree. I've tried to grow it from seeds unsuccessfully. All of ya'll look fabulous!

Gina, I've just done a quick look around online and they are shown as available in various sizes and prices from:

- Etsy vendors
- eBay vendors
- Top Tropicals
- Eureka Farms

I hope that helps. Be careful with a couple of the eBay or Etsy listings, some of these vendors seem to be confusing the Hong Kong Orchid Bauhinia x Blakeana or even Bauhinia variegata with true Bauhinia monandra. Sometimes pictures of multiple species will appear with the same listing, which is of course a caution flag!

[metalfan]

mnorell, I usually buy from Top Tropicals. I've gotten several Bauhinia from them. The Monandra comes and goes with them. Its $50 right now...I think I'll wait for a sale LOL.

I don't buy plants off of ETSY and eBay very often. well, eBay never, ETSY only occasionally and usually from FL vendors. I fond the plants overpriced for the size. And, yes, I find them often mislabeled.

I just got this new croton at a local plant festival here...it is being sold as 'Red Jester'. I saw it on ETSY labeled that too, 'very rare Red Jester'...and I saw that Gabriella plants is selling it as Red Jester. But I had someone who is really pretty expert in ID'ing crotons take a look at it because I could find no historic reference for Red Jester, only to Croton 'Jester' which looked nothing like this plant. It turns out what I bought is Croton 'Interruptum' most probably...possibly 'Coral Showers'...(which IS rare)...time will tell...if new growth comes in with yellow and pink it may be Coral Showers, if it starts red and black with maybe only little yellow or no yellow...Interruptum