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 Introducing myself, plus Tibouchina query 
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Joined: Mon Nov 20, 2017 6:51 pm
Posts: 4
Location: Camberwell, London, UK
Post Introducing myself, plus Tibouchina query
Hi all,

Firstly, let me introduce myself. I've been lurking here for the last few years while developing my garden in Camberwell, in south London, and learning loads in the process, but now I'd like to engage more with the forum. My gardening interests, like everyone on this forum, are growing exotic, rare or unusual plants and pushing the boundaries as to what I can get away with growing in my central London inner city garden. I'm also interested in finding out more about the botany, botanical history, and taxonomy/classification of the plants I grow, and plan to share what I discover on my new blog, http://www.backyardbotanics.co.uk

To that end, I have a question for you. I grow two species of Tibouchina - T. urvilleana and T. organensis. Both are doing well unprotected outdoors, in a sheltered raised bed near the house (they get wrapped in a bit of fleece if frost is forecast). Both are flowering at the moment, but the trouble is I can't tell the difference; the two species look identical to me.

Does anyone know what the difference between the two species is, or is it possible that plants sold as T. organensis are actually T. urvilleana, or vice-versa?

"T. urvilleana":

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T. organensis:

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Last edited by JonathanG on Wed Nov 22, 2017 5:54 pm, edited 1 time in total.



Tue Nov 21, 2017 9:04 pm
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Joined: Tue Oct 30, 2007 10:03 pm
Posts: 1364
Location: Inland Cornwall UK
Post Re: Introducing myself, plus Tibouchina query
Welcome to the board Johnathan.

I think your first link to your blog needs the syntax revising. I think you have a 'spare' full stop just inside the [/url].

Tibouchina is a fiendishly difficult genus for botanists. If you look at The Plant List listings much of the page is 'unresolved' including Tibouchina organensis Cogn. which implies Kew don't yet have an answer! There isn't yet a definitive monograph to work from.

Of the shrubby Tibouchina available in the UK there two forms of urvilleana circulating. The one with larger flowers is probably Tibouchina urvilleana 'Edwardsii', and the other is the 'straight' species.

There is also material with larger leaves that holds its smaller flowers in a panicle rather than individually [OK urvilleana is also in a panicle but usually only one or two flowers are open on one panicle at a time]. This has been known as Tibouchina grandifolia [possibly an invalid name?] and more recently as Tibouchina heteromalla. I have no idea how accurate those suggestions are though.

Just establishing in UK cultivation is the dwarf hybrid Tibouchina 'Groovy Baby' which may prove hardier than the others.

I think both of your plants are Tibouchina urvilleana.

I have fond memories of Camberwell, I lived on Coldharbour lane for a couple of years when it was a cheap area just after The Brixton Riots, before moving north of the river [and then to Cornwall!].

I'm guessing I couldn't afford to live there now!

Chad.


Tue Nov 21, 2017 10:05 pm
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Joined: Mon Oct 29, 2007 3:59 pm
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Location: Loughborough, Leics, central UK
Post Re: Introducing myself, plus Tibouchina query
Hi Jonathan,
Welcome to the forum nice to hear of your exploits with Tibouchina a plant I am going to try outside here in Leicestershire next spring.
T.grandifolia is big on all parts we have only ever seen one in Madeira a fab plant to try.
What minimums do you have to endure during winter I am guessing not to bad at all given your location?


Tue Nov 21, 2017 10:48 pm
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Joined: Sat Mar 29, 2008 1:42 pm
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Location: Cornwall
Post Re: Introducing myself, plus Tibouchina query
I agree with Chad, both your plants look to be T. urvilleana indeed all the organensis plants I have seen being sold in the UK have so far proved to be urvilleana, I am not sure what the botanical difference is but we saw several plants of organensis while in california and it looked completely different
Image

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Wed Nov 22, 2017 7:45 am
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Joined: Mon Nov 20, 2017 6:51 pm
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Location: Camberwell, London, UK
Post Re: Introducing myself, plus Tibouchina query
Hi all,

Thanks for the really useful responses!

The lowest winter temp I've had in the 5 years I've lived in Camberwell is -4C, though a couple of winters have been almost frost-free. Last winter was probably the worst as a frost came early (Nov I think) and later in the winter we had about 2 weeks sustained at around 0C or below. Still, no casualties so far...

Wow, I'll definitely be trying T. grandifolia/heteromalla next year, what a beautiful plant!

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Thu Nov 23, 2017 7:49 pm
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Joined: Mon Oct 23, 2017 9:29 pm
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Location: cantabria spain
Post Re: Introducing myself, plus Tibouchina query
Hi there:
Does anyone know if Tibouchina urvilleana is synonym to T. semidecandra?
Thank you

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Julio


Fri Nov 24, 2017 9:45 am
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Post Re: Introducing myself, plus Tibouchina query
Yes, plants used to be sold under that name. Plant finder entry is Tibouchina semidecandra hort - see T. urvilleana.

Similar problems with T. grandifolia and T. heteromalla I can see no difference in plants of either name

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Fri Nov 24, 2017 10:28 am
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Post Re: Introducing myself, plus Tibouchina query
Thank you, Charlie, for the quick answer.
Garden centers here, always sell them under that name: semidecandra.
Recently, I bought a tibouchina with much smaller leaves. No name, but I think it could be Lepidota. I´ll try to post a picture later.
Thank you.

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Fri Nov 24, 2017 3:30 pm
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Post Re: Introducing myself, plus Tibouchina query
Thank you, Charlie, for the quick answer.
Garden centers here, always sell them under that name: semidecandra.
I planted the one in the picture, some, four years ago.
Recently, I bought a tibouchina with much smaller leaves. No name, but I think it could be Lepidota. I´ll try to post a picture later.
Thank you.
Image

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Julio


Fri Nov 24, 2017 4:10 pm
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Post Re: Introducing myself, plus Tibouchina query
Hi Jonathan G.
It´s amazing that you have tibouchina growing outdoors. The first one I planted a long time ago, got fried it´s first winter, and I am supposed to be in a 10A USDA zone. The one in the picture has been in the ground for four years now. It is sheltered by a wall and a castor bean (Ricinus) above. So, as you already know, keep it sheltered in winter and you won´t have any trouble.
Does yours flower all year round?

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Julio


Fri Nov 24, 2017 5:26 pm
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Post Re: Introducing myself, plus Tibouchina query
julrodmes wrote:
Does anyone know if Tibouchina urvilleana is synonym to T. semidecandra?


Charlie's answer is correct but incomplete.

Tibouchina semidecandra Cogn. is a perfectly respectable and distinct Brazilian species the 'Cogn.' at the end gives the publication authority for the name. In this case 'Cogn.' is Alfred Cogniaux (April 7, 1841 – April 15, 1916) a Belgian botanist who wrote 'Melastomaceae'. (G. Masson, Paris, 1891) and is the first author for a lot of the Tibouchina.

Plants grown in Europe from the late 19th century were misidentified as this species and widely circulated as Tibouchina semidecandra. Once the mistake had been discovered there was no easy way to 'lose' all the horticultural references to the wrong name. So, we have Tibouchina semidecandra Hort. Here the 'Hort' as 'authority' means 'the plant grown under this name in horticulture, but we know it isn't right'.

So as Charlie wrote, Tibouchina semidecandra Hort. is the same as Tibouchina urvilleana Cogn. BUT,

In Brazil [and let us hope nobody introduces it to Europe] they also have Tibouchina semidecandra Cogn. which is a different plant.

Just to cheer you up, the genus is due a systematic review and all the species we grow in Europe will need new names! A comprehensive genetic review from 2012 has suggested the whole of the Melastomataceae need reviewing and the Genus boundaries will be redrawn. None of the plants we grow will get to stay in Tibouchina. This vast academic undertaking is unlikely to happen soon though, so we should be OK for several decades with the current names.

Chad.


Sat Nov 25, 2017 10:42 am
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Joined: Mon Oct 23, 2017 9:29 pm
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Post Re: Introducing myself, plus Tibouchina query
Hi, Chad:
Thanks for your very interesting and accurate answer. It´s good to learn new things.
This is the "new" Tibouchina I bought the other day with no name and, later, I saw it in a different garden center, under the name of "Urvilleana".
Finally, after searching in the internet, I found it "must" or "can" be Tibouchina "Groovy baby", a new selection carried out by Australians. See this link: http://www.pma.com.au/Plants/Plant.aspx?plant_id=1192604178
Heres is the picture:

Image

Have a close look at the small size of the leaves:

Image

I hope it is of interest to you all.

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Julio


Sun Nov 26, 2017 3:35 pm
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Joined: Mon Nov 20, 2017 6:51 pm
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Location: Camberwell, London, UK
Post Re: Introducing myself, plus Tibouchina query
Hi Julio,

No, mine doesn't flower all year - the winter knocks it back and it only recovers in time to flower by the following autumn. I'll let you know if it survives this winter. If not, I have a few cuttings on standby on the windowsill...

'Groovy Baby' certainly looks interesting, nice and compact - another one to add to the collection next year!

Jonathan

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Thu Nov 30, 2017 5:25 pm
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