I have just bought some blueberry plants, they are to be potted up to 3 ltr pots and the info suggests mixing rotting bark chippings - ideally pine, with ericaceous compost.

I have been to loads of garden centres, b&q and searched the web but I cannot find any "rotting bark chipping" - certainly no pine based mulch. I know you can make your own but that takes 1 - 2 years and I need to pot now. I have come across bark in various forms inc pine but they are all decorative or play surface types, any guidance appreciated, ideally a web site were I can buy online or brand names/grades so I can search

Thanks for your advice