What size pots?

[igorina]

Hi all,

I have bought:

buddleja davidii
raspberry
blackcurrent
blueberry
redcurrant

plants from POUNDLAND!!!

My questions are:

1. what size pots will they need to prevent me having to repot them?
2. I have one of each will i need to get more of each to ensure pollination?
(or is that just trees)
3. Which ones apart from the blueberry will need ericaceous compost?

I have 3 square planters approx size 15" will i be able to use these?

Thanks everyone...