Hi Avril! I think you'd best buy a suitable sized pot for the plant as it is, and just keep repotting it as it fills the pot. That way you won't have any trouble with wind-rock. Acers hate being rocked by the wind. :)

Thank you Cottagekaren . What is a suitable size pot? I have one that is 42h x 34diameter but I'm not sure it's big enough.

Just depends on the size of the rootball of the plant you are potting up Avril. Use one that is maybe 3-5 cm bigger all around than the plant root ball. :) Then keep moving it as it grows, into a bigger pot with a similar clear area around the roots.

I.e., if you get an Acer in a 25 cm pot, pot it up in a 35 cm pot. Move it up by 10 cm every 1-3 years, as needed. Acers in containers need more feeding than when grown in the ground: a slow release, acid forming food is usually best. You may want to be ready to wrap the pot in bubble wrap in the winter, to cut down on freeze-thaw episodes, which can damage both the pot and the plant.

Thanks Tugbrethil, you've explained it much better than me! :)

Thank you both. This has been very helpful.

If the pot you want to use to plant your acer in is too big - Pot as described by Tugbrethil in a suitable size black plastic pot and sink that in to your too large ornamental pot. As the plant becomes root bound it can be moved on again without any bother. It will also be safe from wind rock. Use annuals to fill the spare space until you need it. Ornamental pots are very expensive and you may not want to end up with lots that are on the small size.

Scotsgran's suggestion is great, with one caveat. If there isn't a fine mesh screen over the drainage holes of the inner pot, the roots will grow through, grow big, and give you fits when it's time to change pots!

Team work works Tug. Good point about avoiding roots growing through the bottom of the nursery pot. If the patio pot is bulbous shape it might be a good idea to always keep it in a secondary pot because it will be impossible to extract the plant without breaking the pot.

Many many thanks.