From what I read in my motley collection of gardening books, now is
not the time to be cutting this plant back but can anyone tell me what
I risk if I do so?
I'd like to cut it back quite close to the wall since it's now
billowing out well above plants beneath it that are consequently being
starved of light. I gather that a radical pruning like this will mean
waiting a couple of years for flowers but since this job will have to
be done, I'd like to start it ASAP and wondered if I could take
advantage of a head start with some summer growth. Most of the leafy
growth (I've recently trimmed off the dying flower heads) is on stems
that protrude about 18" to 2 feet from the wall, so my planned
pruning will leave the wall with just the clipped stems showing. Could
I do it now or in autumn or is winter the best?
How close to the wall can/should I cut?

thanks for any input..