TOW Roscoea

Mary Sue Ittner
Fri, 14 Feb 2003 08:29:51 PST
Dear All,

Here are a couple more notes on Roscoea from the Trillium list that the 
authors have given me permission to share:

"Brian wrote:

  They must need "proper" dry winters.

And I now "wonder" what "proper" dry would mean.  Since EVERYONE knows it
rains without end in the Pacific Northwest (we are currently concerned about
another possible drought year) and we here are officially a Zone 8 but some
of us "think" that is usually too large a number one could conclude we are
not Roscoea country, but one would be WRONG.  WE grow at least 6 supposedly
different ones but...some may be in fact identical.

They are slow to emerge and may "want" warmer summer soil than some get here
in the shade, but they are persisting and self sowing to the point of being
"invasive" by some standards.


Russell Graham - Purveyor of Plants - - Zone 7 - Salem,
Oregon          <grahams@OPEN.ORG>


"In regards to your Roscoea question, we have had a reasonable amount of 
success with several species of Roscoea and one hybrid.  They are all 
growing in partially shaded conditions in a humus rich, though freely 
draining soil.  Pretty much all of them are very
slow and late to emerge in the spring - some waiting until June.  I 
personally think that Roscoea along with some of the Arisaema, (eg. 
A.candidissimum and A. fargesii), that have a similar habit of appearing 
late represent a genetic link between plants and animals.  Just as many 
animals can sense fear, so too can these plants.  Just as they sense my 
fear and anxiety that they won't return, they begin to nose through the 
ground, and this represents still another link - they feel pity.

Anyway, we are growing the following species in our Zone 5 gardening in
western Massachusetts:

Roscoea aff. tibetica TEC 071-00
Roscoea alpina
Roscoea auriculata
Roscoea cautleoides
Roscoea humeana
Roscoea purpurea
Roscoea tibetica
Roscoea x beesiana

Hope this is helpful.  I too am curious to hear what other experiences
people have had with this fascinating genus.

Tom Clark
Gardens Supervisor
Botanic Garden
Mount Holyoke College
South Hadley, MA 01075          <tclark@MTHOLYOKE.EDU>

ps I found a couple more posts
 From Australia

Hello All, Just 2 cents' worth about roscoeas from down under. My mintemp 
is only -3C (occasionally a little lower) so I can't add anything to the 
hardiness question. They grow like weeds here too, especially RR. 
scillifolia and cautlioides, seeding all over. I grow mine in shade, well 
drained but very moist through winter. Of those I grow (much the same list 
as others have mentioned,) my favourite is the large, white R. purpurea v. 
procera, originally from seed from Joe Elliott's wonderful "Broadwell 
Alpines" nursery. The ground colour of white is striped down the lip with 
bright purple. Maddeningly, it has not set seed for me in 30-something 
years, except ONE year, when it set seed then died! (Do plants KNOW their 
time is up and produce propagation material to compensate?)
Anyway, I literally lost (mislaid) the seed but was able, a few years ago 
to replace the tuberous roots from a friend who'd had it from me in the 
first place. (Good reason to share things around!)
For now, I'm looking forward to when that fabulous R. `Red Ghurka' is 
available, and to the exquisite pure white form of R. humeana, pictured a 
few years ago in the Alpine Garden Soc Bulletin.
Cheers, Lesley - 


 > This genus also is a late starter for me, just like Arisaema
candidissimum and fargesii. Other tropicals, now outdoors in my garden (USA 
zone 6)
 > covered by very thick mulch, that do not start to grow until summer is
well on its way

I am interested that Roscoea are OK in zone 5 and 6, as I have lost
cautleoides 2 times, and beesianum, in pots left out of my cold frame by
mistake in past winters. Other roscoea have survived OK planted out in
the garden. They must need "proper" dry winters.

Brian Whyer, zone 8'ish, Buckinghamshire, UK

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