Re: Acanthus

Sean has it right on target though I would add that with supplemental water, I would expect Acanthus to persist through the summer even in your heat, especially if planted in some shade. I've seen them growing in the dry shade beneath oak trees down in Tecate where summers are unbearably hot yet they retain their green leaves all summer.
If you let them go dry, they will die back but not for long - maybe mid July through mid September - then sprout again.
Personally, I love the seasonality and it is a perfect example of adaptability - die back to escape summer heat and return once cooler temps prevail. 

Nan




On Aug 29, 2007, at 3:17 PM, Sean A. O'Hara wrote:


Hi Carolyn -
Acanthus are generally listed as hardy in USDA zones 6-10, or Sunset Zones 5-24. Some species are hardier than others, but I suspect you will have no 
problem with any.
I would expect that Acanthus would prefer to go completely summer dormant in your area. In the Bay Area, these perennials can often be more or less 
evergreen due to our milder temps and if the flowers are cut out and
supplemental water is supplied. But these plants go completely dormant (dying back to roots) in their native Mediterranean and therefore can take high 
summer temps because of it!
Do keep in mind that the roots tend to persist and new plants often sprouts from any piece left behind of severed from the parent (i.e. through digging, etc.). I find this a wonderful plant but I have had many client complain about it's 'invasiveness' (really just persistence in a place they moved it 
from at some point).

Seán A. O'Hara
sean(at)gimcw.org
www.hortulusaptus.com
(ask about mediterranean climate gardening forum)


Perhaps this topic has already been considered and has slipped by me,
but I'd appreciate any relevant comments.

I live in the Sonoma valley of California, between Santa Rosa and
Sonoma, and am considering planting a group of Acanthus plants, probably 
Acanthus mollis.  We have hot summers - as high as 108 F for a few
summer days every year - and my particular location is subject to winter temperatures as low as 20 degrees (rarely) for brief periods. Water is 
available, but not unlimited.
How hardy is Acanthus? Are species other than mollis a better choice? 

Thank you.


Carolyn Stone
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