With nearly all shrubs or climbers it is usually easy to tell if a
branch is still alive by stripping off a small piece of bark. If it's
green underneath it's alive, any other colour it's not.

But that "rule of thumb" does not appear to work with clematis. They
usually show a dull sort of yellow colour - never green - when I scrape
away a bit of bark. Yet they are alive and growing well above the
scraped point.

Is their internal structure different from other plants? If there are no
green leaves on the branch, how can you tell if that piece is alive or not?

--

Jeff