A lot of this depends on what kind of Austin Rose you have. I have 6 Austins in pots currently. I planted them in 20" plastic containers that you can buy at your local Lowe's or elsewhere. Just buy some moisture control potting soil and mix in some RoseTone or other light rose fertilizer and/or compost mix and you should be good to go.

Have you considered leaving them in the garden soil till they go in the ground in 3 months, and using a simple method, like a wick (as described by tapla) to avoid a perched water table and thus permit robust root development? http://forums2.gardenweb.com/forums/load/contain/msg0914024623640.html https://www.houzz.com/discussions/1405347/container-soils-water-movement-retention-xiv

Yes. You probably should not have put this in design dilemma but no big deal.

first.. i always let a new plant acclimate to my house for at least a month.. its stressed from the move ... let it de-stress ... second ... if it grew that way ... who am i to think i need to bury the roots it put.. where it wanted it .... being new.. you might be on the verge of loving it to death .... just learn how to water it properly .. and you should have 99% success rate ... start messing with it.. you will reduce said rate ... ken ps: the odd yellow leaves.. may have been if it was grown on a bench with a hundred others.. and it was pulled out for sending to the seller ... ignore such.. unless 75 of the leaves start yellowing .... its just nbd right now ... [i like the bench idea.. because of the way it is set in the pot .... like some plant next to it was growing on it ...]