On 10/06/2011 04:24 PM, Martin Brown wrote:
On 06/10/2011 15:14, Spider wrote:
On 05/10/2011 19:14, Emery Davis wrote:

I'm looking for the hardiest possible weeping rosemary cultivar. To
drape down a low wall. We very occasionally see -15C. Any suggestions?

I grow Rosmarinus 'Severn Sea', which Jekka McVicar's site call "frost
hardy". However, it has survived in my garden for 4-5 years, despite the
heavy snowfall and frosts of the last two winters. It is on heavy clay,
but at the front of a retaining wall, perhaps similar to your intended
site. The wind often whips it and tosses it back on itself, so it is
fairly exposed. There was a tiny bit of damage last year, but the plant
is doing well. It has the most beautiful blue flowers

In my experience it isn't winter hardiness that kills it so much as wet
feet and/or a nasty white fungal branch rot that starts from the top.


For sure it doesn't like wet. Even in the dryest spots here I can
usually only keep a plant for 5 or so years before it dies off. The
usually do fine until then and then die quite suddenly. We don't get
white fungus, just die back over big sections.

The wall where it's going is however exceptionally well drained even in
winter. It's got bulbs in spring which do OK if there's rain, but
beyond that I've managed only sedums, sages, thymes and a couple of
pinks. So rosemary seems an obvious choice.

Dry continental style cold probably won't harm it but many days of cold
damp conditions lingering around freezing point will.


Conditions here are actually not dissimilar to parts of Devon but a
couple of degrees colder. -15C is very extreme, in any case we haven't
seen that for any sustained period. (I guess I've seen it a couple of
times over 20 years). It's my "absolutely safe" limit, really; I used
it because Fillipi mentions several rosemaries good to -15C but all upright.

We grow many zone 8 and even a few zone 9 plants, although the winters
before this last one were very hard on the garden and I did lose quite a
few established ones.

-E