In article , ned wrote:

Yes, I appreciate that Nature offers a wide range of variation.
'Just thought that the 'splitters' might have come up with a twee
definition.
But I'm happy with the concept that while the leaves and stems of a
'herbaceous perennial' may die back seasonally, its rootstock can last
several years.

There are definitions for plants where the growth point during the
dormant season is below, at or above soil level, which is what is
being asked for, but I now forget them and they are rarely used.
There is also the problem that many plants will behave in different
fashions according to conditions - e.g. many plants will grow from
their stems after a mild winter but from their roots after a hard
one.


Regards,
Nick Maclaren.