Compost for large 60ltr tubs

I have three portugese laurel that I am going to plant in large tubs to provide shade alongside my conservatory. Anyone suggest a good tree and shrub compost please.

 

Thanks JWK, I was thinking of John Innes but just wondered if anyone had any other suggestions. Best to stick with the tried & tested I suppose.

 

I use a mix of general purpose and John Innes No 3.

 

The issues (which I, and I expect @JWK too, think that JI#3 solves) are:

Retains water
Drains well
Can be re-wetted if it dries out
Provides for the plant over a long period - many seasons
Enough weight to stop pots falling over / blowing over easily

MPC and the like fail all-bar the first. Folk use MPC in containers and hanging baskets for the Summer - its a lot cheaper, and it will be watered every day, and fed often, so the other problems are not an issue

 

Maybe I'm just a cheap skate. I just use good garden soil, manure and plenty of well composted leaf mould for my huge tubs. To buy bagged John Innes and the likes would cost a fortune to fill my tubs. I have had all sorts (Tree Peonies, Lillies, Acers plus loads of other types of bulbs grown in the tubs for years and all seem to do fine. I do top dress with a doze of manure in the Spring and have plenty of stone in the bottom of the tubs for good drainage. That said perhaps you aren't fortunate like me to have the room to make/ access leaf mould etc. I would certainly reiterate what Kristen and JWK have suggested re John Innes No 3 if you don't have a source for leaf mould/compost/manure. I find trying to rewet pots of plants grown in a peat/peat substitute medium all but impossible to rewet other than to "drown" them in a big butt of water. Not easy trying to do this with big tubs!
Only a suggestion but maybe this Autumn try and collect leaves and put them (best wetted) in black poly bags. Piece a few holes in the bags and then leave then somewhere out of the way but still outside. With any luck dependant of the variety of leaves, you will have useable leaf mould by this time next year. You could then use this to top up the tubs as I find newly filled tubs always settle considerably and need topped up after a while.