Just moved into a new house and there is a small - big enough to sit out
with a plastic garden table and chairs - balcony outside our bedroom.
The sides of the balcony are covered by a Clematis which is growing from
ground level and has a trunk as thick as a small tree. It had overflowed
onto the balcony and had actually covered a small conifer growing there
to the extent that we only noticed it's tip poking out from the Clematis
several days after we had moved in!

I have liberated the conifer to the patio and cut the Clematis back from
where it was overflowing onto the balcony - including where it seemed to
be growing behind the gutter and into the roof - it is still 95% as it
was. I would like to seriously prune it back, but how brutal can I be
without killing it and when? The house is rented and the landlord might
object if we start killing his plants off.

Brian and Sue.