Am presently limiting slug/snail damage safely with egg-shells and coffee-grounds, although some plants dislike latter. Never lost established shrub due to root damage though, and agree that wild-life is probably best defence.
slug pellets do kill them, but slugs are surprising mobile, and more will gallop in overnight to replenish the stocks. Over a period of a couple of weeks, you will see the population drop, but you have to continue scattering them, especially round the borders of your plot, to kill the adventurous ones that come in. Scattering under a hedge is useful as there is protection from light rain, and they are somewhat concealed.
I'm not sure this is the right time of year for nematodes and, anyway, this summer has been di wet that they are likely to have been washed away. There are recipes online for making your own nematode soup (not for the squeamish).
You can try torchlight slug hunts, but that will only find a fraction of them.
I've had no luck with copper tape, oats, ash or any of the friendly methods. Have resorted to baiting with dry cat biscuits (slugs love it but make sure the cats can't get to it too) and then salting them. Not nice but v effective.
A beautiful and mature colourful shrub (Cytisus sp?) fell over, I thought it was the recent strong winds but the exposed root was teeming with big shiney black slugs. Looks like they have eaten their way through the whole root. It's a particulary wet bit of ground and north facing so I have trouble getting anything new to grow there. This shrub had been planted by the previous residents and was really well established so I am gutted at losing it.
So - how do I kill them, no beer/bran/blue pellets/copper please 'cos these all failed already - and does anyone have ideas for slug resistant shrubs that dont mind the damp and cool - thanks!