[tode]

Whitehartlottie, I really wouldn't put the rasps beside a 'permanent' bed.  You'll always get a few runners coming trough (in my experience).

If you can manage it, it's better to have a tempory planting, like salad, or peas (something that you'll dig up at the end of the year anyway.

Good luck

[Poolfield2]

What is the furthest from parent plant that you have found a "feral" raspberry? Can anyone beat my 6metres?

[tode]

I think that must be a record           

I've always wondered if the raspberries don't grow from seed.  There's no reason they shouldn't, I suppose.   Every year I find a few blackberry plants popping up in unexpected places.

[JayG]

I've always wondered if the raspberries don't grow from seed.  There's no reason they shouldn't, I suppose.
 

Just Googled that out of interest, and yes, they can be raised from seed. (Wish I hadn't, by the way because I am in the habit of chucking over-ripe raspberries down the side of my shed!) 

[Nobbie]

PVC Soffit boards from Wickes are good as a barrier, they come upto 12" wide and in long lengths. Just bury these by the side of the raspberries and make sure you overlap the joins well and tape up. If you leave a gap they will find a way!

[whitehartlottie]

have been looking on line for plastic liners and this place: http://www.pondlinersonline.co.uk seems to do different types of plastic cut to order. Its a cheaper option than soffit anyway. The pvc is cheapest - now just have to decide how deep to go, probably will overcompensate as I really really don't want them escaping into the asparagus bed.