Bay Tree Blues

I have two large bay trees that are about 40 years old. They're in half barrels that are beginning to rot round the sides and the time has come to repot. The cost of new planters will be £300 so I need to ensure that I don't lose the trees in the process of resettling them. Has anyone had experience of repotting trees of this size? The new pots are deeper but around the same circumference.

The main things I need to know are:

Is autumn the best time to repot them?
Can I trim the roots?

Any advice would be most appreciated. Thanks

 

Bay trees are very, very tough so, yes, I would repot asap. Gives them time to settle before the winter sets in. Often said that bays are impossible to kill; a reputation that gives more than a clue you wont harm them alana
The rotten barrels? They should be easy to dismantle without damaging the trees.
I would trim any long, damaged or congested roots as well as the top. I would also use john innes number 3......not mpc

You dont say how big the trees are but prob will be a two man job ​

 

Thanks @Verdun - that's good news. I wasn't worried about them coming out of the barrels because if the bands are cut they will fall apart. I have someone to help me so that will be a job for this week.
This picture was taken last year when the planters were still together. The tree in the foreground is the twin to the other on the right hand side of the image obscured by the pots.

 

Yes, we have a 4m high Bay in a 24" internal diameter half barrel and have repotted it twice. I can't rember the first time, and can't remember exactly how I did it last time, but Mrs Scrungee has just reminded me it involved a pallet, lots of alcohol and extensive swearing.

I think I pulled it onto its side, removed the remains of the previous half barrel, trimmed the roots around the perimeter to enable addition of some fresh soil, and dragged it (still on its side) onto the pallet.

Then I placed the new container on its side and got Mrs Scrungee to hold it in place whilst I pulled the rootball into it, then pulled pot and tree upright. Mrs Scrungee then stood back to give directions on getting it vertical and I packed some fresh John Innes around it.

 

The new pots are being delivered late today so there'll be lots of swearing going on here. We've prepared by moving the half barrels with the help of one of those round things (don't know what they're called) used to move white goods. One of the barrels had rotted through the bottom and the roots were going through a crack in the patio. With the help of a crowbar and our new pruning saw we freed it.

Fun and games but hopefully it will be worth it to see the trees in their new, upgraded home.
I'll definitely need a glass or two after this fiasco

 

Lights back on the bays now and blues over.
When I looked out of the window at my new pots this morning, I saw this little visitor using this one as a perch. He's giving the planter a sense of scale - they are biiiiiig

 

Perfect alana .......great pot too.