yes
they can be sherdded but before you think of add to the border , ask are there any sign of diseases as this will be the biggest problem if it was me I would find a better way of removing the pruning,

You could shred and then put on paths in your veggie garden. I'd be concerned at putting on a flower bed just in case their is any disease.

Thanks for your comments Jonbridge & Moon growe. Looks like a run to the tip.
Very good site,only came across by accident. Will use it again

Note also that the thorns can last for years, even with composting.

That is true TugB. - bit like holly leaves

if your roses have black spot id be very careful.....roses are prone to disease

Fresh, shredded material should never be added to the soil, either as a mulch or dug in - it will rob your soil of nitrogen, leaving your plants short. Compost them. Same applies to any woody shredded material.