Hi Toni. All clerodendrums bloom on new growth. I prune them in the fall when moving them into the greenhouse. I sometimes prune them again in the spring before setting them outside if the winter growth looks scraggly. I have several varieties, including 2 varieties of C. thomsoniae. One of the things I like best about clerodendrums is how different they are from each other. A C. ugandense and a C. quadriloculare look nothing like each other. I don't grow them as houseplants. I keep them outside in full am sun during the warmer months and either in the greenhouse or dormant over the winter. I feed them a balanced fertilizer every few weeks during the growing season and keep them well watered. My newest is very similar to C. wallichii (Bridal Veil) but has much larger blooms. It's a C. smithianum (Lightbulb flower).
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Hello Karyn and thanks.

The flowers on your Clero are so, very pretty. Much different than thomsoniae. How large do C. wallichii blooms get?

Would you happen to know if thomsoniae's are summer or winter bloomers? Depending on bloom season may make a difference when leaves should be pruned. The reason I ask, 'even though you said yours goes dormant in winter,' the last Clero I had, (mid-90''s) bloomed in Feb. A little early for spring, right?
Also, how much do you prune off?

Did you say you placed thomsoniae in full sun? My first Clero burned in the shade after being outside for months. Same location, under a tree.

Before starting this thread I Googled Clerodendrum. Several pics popped up. I had no idea there were so many species. I'd LOVE to get my hands on a variegataed Clero, but never heard let alone seen one before yesterday. Wonder if variegataed grows as fast as green??

While on Google, I came across a site that stated Clero's can be shaped into Standards. Of course, there weren't pics or instructions. Would you happen to know how?

Clerodendrum leaves are nice-looking, but would be a lot more interesting growing tree-like rather than attached to a trellis.

You said you allow Cleros to go dormant in winter. Do you stop watering completely or reduce and withhold fertilizer?

Karyn, I'd take it outside in summer but fear it'll burn like the first Clero. If you think setting outdoors will promote blooms, it's worth a try. The only problem is location. The shadiest spot is directly under our Maple..'the sane spot the other Clero burned.'

When you prune foliage, do your root prune, too?
My Clero is in a 10-12" pot. I'd rather it needn't be potted in a larger container. Room, you know? lol.

Thanks again, Toni

Hi Toni,

My Thomsoniae's are summer thru frost bloomers as are all my others. C. wallechii flowers are probably about 1/4" when fully open. The smithianum are about 3x that size. I love C. quadriloculare but don't have a long enough growing season for it to bloom well and it doesn't do that great for me in the greenhouse over the winter. All the others I have do fine. I allow thomsoniae and ugandense to go dormant over the winter. I stop feeding all of them around Sept and water the dormant ones very infrequently. Ugandense actually blooms well under lights but gets too big over the summer for me to move it without cutting it back. The variegated thomsoniae shouldn't be difficult to find. I think mine was from Zone 9 but am not sure. Mine grew a bit slower then the standard but not by much and the blooms are the same. My thomsoniaes are in bigger containers. I've never root pruned and occasionally just leave them outside to die over the winter. They get really big and are fast growers so it's not a problem starting with a new plant in the spring. My standard thomsoniae is still outside and I haven't decided if I want to move it or not. It's in a 27" pot and is a PITA to move. I've never tried to train one as a standard but assume you would do it the same way you'd do any other woody vine. I'd try and slowly acclimate it to at least full am sun if you want flowers. Maybe your plant was originally started in a shade house or you moved it from the GH or inside. If so even bright filtered natural light will burn the foliage. I wouldn't worry about burned leaves as the new growth outside will be hardier. Almost all my plants suffer sunburn when they are moved from the GH back outside in the spring. Surprisingly many clerodendrums are considered somewhat invasive in the warmer zones.

Hey Karen...I had to laugh when you said you keep Thomsoniae outdoors all winter until it freezes.
We have at least 3" of snow outside, plus temp was supposed to drop 6F last night. If my poor Clero was kept out, by spring all I'd find is a pot of soil..lol.
The only living plants outside now is Holly Ornamental Cabbage/Kale that was planted spring, 2011. Before the snow, Arum was doing well, too.

You're two zones higher..You can probably get away keeping more plants than us zone 5'ers. lol.

Oh, the first thomsoniae was purchased at a seasonal, outdoor green house/garden center. Their plants are brought in from Mexico..
If I remember correctly, their Clero's were under an awning, outside, but I wouldn't call it shady.
The truth is my Clero was under-potted so soil dried FAST. I was working at a plant store, and at times, neglected to water my own plants.

Karyn, do you have a website? I know you have way more plants than I, and would love seeing them.

I Googled other Clero species you mentioned, but I want to see the entire plant, not just tops--leaves/flowers.

Thanks for pruning advice. My Clero is way too big, foliage takes a ton of space.

I stopped fertilizing last autumn and only water when soil is totally dry..it's very dry now..Some leaves are yellowing. 'No insects.' Is yellowing normal this time of year? I'm tempted to prune now, but know it's too early.
Would you wait until late Feb or once new growth peeks out? I know, back to pruning questions, lol.

I'd really like my Clero to bloom before I leave the earth..lol.

What did you mean when you said you think you got your variegated thom in z9? lol. A garden center/store/wild in z 9?

I should recheck other Clero's you're talking about since I've never heard of these types, but I prefer looking at an entire plant from top to bottom.

Karyn, wow, your Clero is in a 27" pot??? How big is your plant? lol. What type of soil/medium is it in?
Do Cleros need extra Iron? Foliage looks like they would, but I could be wrong.

Karyn, about shaping into a standard. I've never tried it, lol.
I have one hardy Morning Glory, 'Blue Dawn' purchased from Logee's years ago. When I got the MG, I also bought a wire, topiary. The topiary pole is tall, then ball-shaped on top. MG leaves climbs up the topiary pole and around the ball. That's the closest I've gotten to shaping.
It's nice, but the cost isn't. Anyway, growing on a topiary isn't what I want. Guess I'll have to continue looking.

Anyway, thanks for all your help. If you have a site, please give me the addy..hugs, Toni