Cut it all down short (maybe 12-18 in.) at the end of winter. If you want a short hedge you can prune it down every year at the right time and it will still bloom.

Drifter, prune as much as you desire..it will bloom.

ROS is an invasive plant...depending on variety.

A neighbor gave me a cutting about 20-years-ago. White/pink flowers.
Two-years after rooting and planting it stood 8-feet. A year or two later, it grew another 8'. Side shoots popped up on mom and various areas in the yard.
INVASIVE, for sure.

I pruned and re-pruned several times spring-fall. The more I pruned, the wider ROS got. lol.
I got pretty fed up, so decided to cut the entire, 'tree,' from the trunk. BTW, I still find ROS in the yard.
A seed found its way between our house and the neighbors...it's doing fine..Stands 5-6'.

I bought a second ROS, 'purple flowers.'
This variety is tree shaped, non-invasive, and remains a perfect size without pruning..

Good luck...hope your ROS doesn't take over your garden. Toni

if you want to maintain some level of privacy ... you cut down every other one this spring ...

and then the others .. next spring ...

i am surprised you have no complaints of a bazillion seedlings all over the yard ...

ken

Ken...The bazillion seedlings are either plucked or dug up. lol. Lots of work.

The ROS on the side of the house, between neighbors' and ours, is okay..All that grows along the path are weeds anyway, and closer to my side is a Peony.

If you cut off every other stem you will be able to see right through the hedge, making this pointless. You will also be looking at plants consisting of a mixture of tall, open original stems and bushy new growth.

no.. just cut down every other plant in the hedge ..

yes.. you will remove 50 % ...

but you leave 50% more sight blocking.. than if you cut down the whole hedge..

heck.. i dont know whats back there ... maybe some 400 pound nudist.. of which i might prefer to see only 200 pounds.. lol .. [on the other hand.. i might just gouge my eyes out .. lol]

frankly... if seedlings are an issue.. kill them all.. and plant a non-invasive hedge ... crikey ...

i surely wouldnt put up with hours of seedling slaughter .. repeatedly during the growing year.. for decades to come ..... when the same amount of time.. could have me done with the whole .. FOREVER ...

trust me.. you can do a whole lot better than ROS ...

and a method for such.. would be... to remove one or two at each end... and plant replacements.. and then over the next few season... taking more and more.. until you replace the hedge ... thereby maintaining some semblance of sight blocking ...

or do it all at once ...

they are a problem.. you know they are a problem... and you are hoping there is an easy solution.. NO!! .. there isnt.. get rid of them .... lol.. do whatever pleases you .. i am just playing devils advocate ...

listen.. when i bought my first house.. i was going to save all the plants.. for the history of the house... and i dealt with a bunch of nightmares... the happiest day in that garden was about 5 years later.. when i removed the last nightmare... because by then.. i figured out the prior owner was an idiot .. and planted a bunch of nightmares... so once removed.. i planted the next owners nightmares.. and then sold the house.. with the nightmares.. about 5 years later.. good luck with that.. lol ... BUT!!! .. the first thing i did at house #2 ... i chainsawed every bad plant.. the first summer ... live and learn ... and they all burned.. rather nicely ... lol ..

just think about not putting up.. with a bad plant.. just because it is there ...

ken

Ken, you're funny, lol.

Just for the record, there are some cultivars of ROS that are sterile. I have one--'Diana'. It's white. I've heard that all with names from classical mythology are sterile, but i can't swear to that.

Thank you for all of the responses. I'm happy to hear that I can hack freely since pruning the hedge branch-by-branch would take forever. Eventually, we probably will replace the plants with something more appropriate, but for now, they provide some privacy and visual interest during the summer months.