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Re: Dahlia imperialis

Just for the record, D. imperialis survives outdoors in Seattle with
little problem, other than the fact that we very rarely get the heat units
to bring it to flower.  Our winters are extremely wet but it doesn't seem
to faze it.  Our winters average around 40F (4C), but can get down to
6 or 7F  (-13C), albeit rarely and for very short periods.  I have seen a 
well-established plant take this, but wouldn't risk it with a new one

Bob  

On Wed, 20 Aug 1997, David Poole wrote:

> I was given a rooted cutting of this species in early June this year
> and having potted it on into a 15" container, it has leapt up to over
> 7 feet high, with 3, 'wrist thick' main stems.  The 2 foot+ long,
> aralia-like, pinnate leaves are very handsome and whilst I do not
> expect to see its pale, white stained mauve flowers this year, I'm
> hopeful that it will perform during next summer.  Frost is a
> considerable rarity in my garden and winter night lows seem to hover
> around 40/45F.  The only drawback may be that our winters are
> generally very wet, with many totally sunless, rainy days.  This can
> cause problems with species that are susceptible to fungal rots and
> various moulds.  I'm not sure whether to dry it off for the winter and
> store the tuber until early next spring, or to try and retain its top
> growth.
> 
> Does anyone have any direct experience of growing this species?  I've
> seen very poor, weedy, 10 foot high specimens growing and flowering in
> Tenerife, but have yet to see it discussed to any extent.  I know that
> it is a sub-tropical, native of Mexico and capably of reaching well
> over 15 feet high, but apart from technical details about this
> species, I can find little else about it.
> 
> I would like to know how cold tolerant this plant is (without any
> detriment to flowering capacity) and whether it can make sufficient
> growth from the roots in one season for it to produce flowers.  Also
> (again related to flowering) how long a growing season does D.
> imperialis need?   Everyone that I know over here, claims that it will
> not flower out of doors in the UK, but having broken nearly every rule
> in the book over the past few years, I'm taking those assertions with
> an immense pinch of salt.  
> 
> I've got money riding on whether I can flower it outside by October 31
> 1998, so any help with this would be greatly appreciated <G>.
> 
> David Poole
>
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