Rejuvenating north-facing retaining wall
Hi everyone, I'm hoping that some more experienced gardeners than me can weigh in on my plans to rejuvenate an awkward spot in my garden. Pictures below - it's a retaining wall, brick at the bottom and then sloping stones up to the patio and shed. There is about a foot wide planting space at the top. The trellis blew down over winter taking a jasmine with it (cut back but I'm not worried if I have to replace it) - other than that the only things growing here at the moment are a sad-looking cotoneaster, a few ferns, a load of saxifrage and mind-your-own-business, a very old rosemary bush and lots of long tatty grass. The section by the patio gets a reasonable amount of sunshine in summer, but the wall itself and the side of the shed are north-facing and get no sun at all.
My plan is as follows:
Remove all of the current planting (except maybe the jasmine if it rejuvenates) and clean up the stones, digging out as much of the weeds as I can.
Treat the rest with glyphosate until the weeds stop regrowing (no flames please - I don't normally resort to weedkiller but the mind-your-own-business is a huge problem in our garden and I don't want to risk it recolonising the area).
Put up new trellis along the patio edge and shed wall and rejuvenate the soil with organic matter. Possibly paint the wall a lighter colour to brighten up the space.
Plant climbers and other suitable plants along the patio edge and shed and tuck some other plants into the stone wall to fill the gaps and tumble over the edge.
My questions are as follows:
How long do I need to wait after using the glyphosate to be sure that I've dealt with all the regrowth? I've not used it like this before.
Any suggestions for plants? I want to grow at least one clematis. I love bulbs in spring. I'd love a climbing rose but access is awkward for pruning and maintenance. I'd prefer climbers on the trellis that cover both sides so we can enjoy them from the patio side as well. Any ideas for the shaded section along the shed wall? How many climbers would you suggest would fit along this space?
What plants would work well in amongst the stone wall - alpines? I know nothing about those. Any suggestions for plants that would be nice to tumble over the edge apart from the obvious ivy?
Thanks for your help - all suggestions gratefully received!