On Sep 17, 4:39 pm, Terry Fields wrote:
ITYM pyracantha.

That is it :-)

I'd suggest putting the fence up anyway, then going for the
pyracantha to protect the fence. Otherwise I fully agree.

It might be possible to get away with a stub chain-link fence.

Once the hedge is established the fence becomes secondary, at that
point it could be rolled up and dispensed with. Perhaps simply wooden
posts bolted into concreted-in ground-anchors with chain-link rolled
over. Just proper fasteners rather than staples to avoid "vandal
peel".

Pay for the largest plants you can get, smaller ones can
easily be ripped up. Feed and water in the growing season.

Indeed. The quicker it is established the better.

I have the same situation as the OP, a single-skin garden wall that
after 40 years is showing signs of distress, crumbling mortar, cracks,
etc. If it goes while I'm still here, I'll put up a chicken-wire fence
and let the 30-year-established pyracatha bushes form into a
continuous hedge.

Very effective, walls are not always the solution they seem.

Security is often for vandals:
In a local town all the small businesses/shops have "7ft brick walls".
They are double brick, but a shambles of crumbling brickwork.
Whilst sat in the neighbouring carpark children flip their hoods up &
climb over, shortly followed by the sound of back doors being kicked
in or a brick pounded against top bricks to remove them. Once one
brick has gone, the wall has no integrity from future attack by vandal
or weather erosion. Three times I have had to call 999, the businesses
have a life of misery with sky high business rates as it is.

Favourite ploy of councils:
Wall gets damaged, council sends letter demanding it be fixed in 28
days or they will do it for you and sue for nulabour rates.
Replacement cost can be horrific, true engineering bricks cost - cheap
frost-resistant stuff looks worse after 1yr than others 55yrs old.
Rebar must be galvanised because mortar provides little resistance
from water penetration - rebar is situated at too low a depth.

Some councils try to apply same to foliage:
Beware foliage growing "1-inch" over a pavement - some councils will
write threatening to cut whatever down & charge. So ensure any
planting is on your ground and keep the plants under control. The good
thing about the plant is a hedge trimmer will rapidly bring it back
into line without effort, ie, you do not need a farmer's trimmer for a
long hedge. It is a bit of a dinosaur plant in that respect, it will
withstand pretty much anything.

Councils do not like press attention to their "cretin with a keyboard
and power and anti-terror legislation", so any trouble and an article
in the local rag or online can really send them scurrying back under
the stone.

A final note - plant some spare plants so if any suffer damage they
can easily be transplanted at a moments notice.