This link provides detailed answers to your question.

http://www.rhodoland.nl/propagating_grafting.en.htm

The chances of them rooting from cuttings are very very slim Kate. Most rhodies are increased by either air or ground layering or grafting.

Chances are that if you go a bit further into the Rhodie and look on the ground, you'll find a naturally layered shoot. You'll need to ask the parky if you can dig it up though.

I'm with Andy, you're best chance is to look for a ground layered shoot. I seem to remember that 'Rootgrow' does not work on Rodos as is has its own fungus around its roots and if you can take some of the soil from around the shrub then it can help to make the cutting thrive by rooting more easily.

Mind you don't get caught cutting bits off shrubs in parks, never mind looking for rooted parts beneath - its illegal to do this without permission.

Ahhh Kate, you are a woman after my own heart...... I'm making an attempt at gardening by propagation too x got my eye on loads of stuff in local area x good luck with parks dept and finding a rooted shoot you can take home x if you don't ask you don't get is my new motto x Mags x

Thanks for your comments but Im going to try with what iv got I have nothing to lose...Bamboo there was a park attendant who I asked permission..I have done some research and this topic is very debatable,however I did find this :
'In public parks, people are encouraged to harvest anything edible, take seeds and small cuttings (in fact, if you are spotted taking cuttings, the park attendant will usually come help you and show you how to do so without damaging anything), and pull up weeds with great abandon. You're also allowed to plant whatever you like in public parks, provided it's not a weed.'
Its always best to ask though :)

Great info thanks for that and keep us updated on your cuttings :) x

That's really interesting, Kate - I knew you technically had the right to plant something in a park that wasn't considered a weed, but I didn't know about the rest, thanks for the info.

Yes keep your fingers crossed for me they are all done..just the waiting game now :)

D'you reckon that means its alright for me to cull a few berried holly branches around Christmas time then? Not sure it fits in the parameters you listed above, lol

lol arhhh just go for it Bamboo a bit of what you fancy does you good!! lol :)

I already do it some years - but I sneak about like a criminal hoping I won't be seen doing it... I only cut about 3 branches, but even so...