"80/20" wrote in message
news:6281605.678.1336336605915.JavaMail.geo-discussion-forums@vbvx4...
In 1995 I planted a Montana (unknown variety) and it has flowered very
well, indeed so well I though I'd plant a second one in a different part
of my garden. (this was in 2003)

Both have perished this year, all my other clematis are doing well,
(Nelly Moser, President, Dr. Ruppel & Etoile Rose)

Has anyone any suggestions as to the likely cause of death?

Montana have a fibrous root system and can rot off if very wet, but is was a
dry winter so maybe not that, also despite being a hardy plant the stems as
they age become thick and gnarly and can rot from the inside out, this will
also happen to any other Clematis that is not cut back hard from time to
time and is due to clematis stems not being a permanent feature but having a
finite life. So although montana and some of the others you listed are "No
prune" varieties I would never the less cut at least one old stem hard back
each year to encourage new stems from the base, if Clematis only have one
stem/trunk it normally means the owner was too kind hearted to chop it down
after planting!


--
Charlie, Gardening in Cornwall
Holders of National Collections of Clematis viticella
and Lapageria rosea cvs
http://www.roselandhouse.co.uk