Type of mulch

Dear gardeners, please help to choose what do I need to buy as mulch for my plants: they prefer different type of soil ( roses, blackcurrants, hydrangeas, lavenders... ) is it ok to use the same mulch as I have read depending on wood used it can turn soil in more or less acid....I have read pine barks are perfect but cannot see them in shops;
Barks, chips, decorative mulch- what should I use?

 

Just found some free woodchips. Everythings been mulched with them . Thinking the woodchip will only take nitrogen from the soil surface so my watering with feed should still get the food to the roots?
Hope so anyway.
Have been using straw up till now.

 

Thank you very much for explanations. I was confused as I have read bark chips will decompose and will turn itto compost for soil... so I though now I mulch it and in 1-2 years I will have compost in natural way.

 

Aha, thank you, good news, will they affect soil in terms of nitrogen? Can they be used for all flowers: those love acid soil and those prefer alkaline? Sorry for a lot of questions but I was really confused after all read on the internet.
And could not find pine barks at all ( probably I have read about it on US websites)

 

I garden on good ol' Essex clay and have used composted bark fines to break up the soil and use as a mulch.
It's worked really well- and smells really nice too
Composted Bark Fines
I'm guessing that as the bark is already composted it shouldn't rob the soil of nitrogen I've not seen any problems), and unless used in huge amounts will not affect the soil pH
I've also seen composted bark in 2 of our larger local GC's

 

Thank you very very much to everyone for your help. Have a nice evening