David E. Ross wrote:
....
I don't know about clematis.

we have several different types and
some are much more aggressive than others
so it really helps to know what you are
buying for these so you can provide
adequate space/trellis support. we have
one which is a late summer white bloomer
with many small flowers. it easily tops
the 8ft trellis. deer will eat it in
the winter if they get hungry enough so
that can trim it back, but it will regrow
each season.

....


songbird