My advice for potting substrata for roses has always been a half and half mix of 'regular' potting soil (i.e. peat based substrata) and good clayish garden soil. I see no reason why this would not apply to you unless you get too much rain during the summer in which case a larger percentage of potting soil might be better. Clay content should be increased the drier the climate is and vice versa. I would not wory about fertlizing them until they properly leaf out and start to grow vigorously. I'm sure others may offer different advice, roses are not very particular with regards to their potting soil.

Roses, in general, like the sun. Just a few hours of morning sun is not ideal for most roses, though that will help with decreased watering needs.

With regards to pot size and since these roses are destined to be planted soon I would not go for a large pot. Just enough to accomodate the existing root system with a bit of room to grow will be enough if the roses are going to live in the pots only for a few months. Say, about 50% larger than the volume of the current root system fill be more than enough IMO.

I don't recommend using top or garden soil at all in pots. It is too heavy and does not drain enough for potted roses. I always use a good quality light weight potting soil. Some potting soils have a slow release fertilizer in them so that should be fine to start out with. You can also use a liquid foliar feed like Miracle Grow about once a month.

BIG pots! Particularly for Austins which tend to get pretty tall. Mine were in pots that were at least 24 inches wide and tall. I have some now that are even bigger, like 3 x 3 feet and those would be better. Get plastic or that light weight resin. A big pot full of wet soil and a full grown rose weighs a TON! Also, put those wheeled pot trolleys under them. It helps with drainage to get them off the ground and, even if you don't think you'll ever have to move them, believe me, at some point you will. The trolleys make that much easier to do!

How many hours of sun are we talking about? Roses need at least 6 hours of full sun to bloom well. Anything less and they may grow but not bloom.

Seil, regarding the potting soil, you are free to disagree, I'm sure this is a very controversial subject and I just pointed out what I have been doing for years (for many tens of roses) and what advice I have given with no negative feedback, but I recognise there may be as many opinions on this as gardeners. I was originally given this advice by a long established rose nursery and it has served me well.

Reason for clay content is water and nutrient retention and mineral
availabilty both of which roses need aplenty while not being
particularly objecting, rather the opposite, to constant humidity in the
substrata ( in contrast to many other plants e.g. citrus that I also grow and for which I would not think about suggesting garden soil in the pot
). My roses have been consistenly performing better with a clay mix, heck even just with clay soil in the pot, versus a quick draining peat or sand based potting medium with small water holding capacity. Watering and fertilization frequency can be more than halved which surely makes growing roses in pots much less of a hassle.

With all due respect though I will strongly disagree with regards to pot weight and size in this particular occasion. Maybe the fact the roses will only be temporarily potted for just a few months has escaped your attention. No need for a large pot which will make subsequent transplanting more hazardous both for the rose and for the hole digger's back.

I thought the bareroot roses, once potted, needed to be kept in a cooler, not quite so hot spot for a while. Is that not the case? I have a west facing patio but it can get pretty hot back there.

As long as they are kept well watered they can be kept anywhere. See what I have been implying?

Wow, I wasn't aware of that this topic was controversial, lol. 99% of my garden is in commercial blow mold plastic nursery pots (7-10 gal to be specific). I'm not peckish about soil, nor are my roses from the outcome of my experiments. I have gone and spent money on the expensive stuff and have also gone the cheap route with equal results. My formula...

I buy several bags of the cheap generic brand top soil ($1.50 per cu. ft). It drains well for me. I also buy a bail of Peat Moss ($10). I found a place that sells large bags (the things are like three to four feet tall and a foot across) of Perlite ($10). I buy a granular fertilizer, something with a low burn blend (6-6-6), or something with insecticide built in like the Bayer Advanced stuff. I blend the top soil (1 cu. ft.) with ten cups of Perlite and five cups of Peat Moss. I add three cups of fertilizer and mix it all up in a wheel barrel. This will often fill up two seven gallon nursery pots. With time I aerate the surface of the soil and poke holes to help water delivery.

This works for me and I'm sure other variations will work as well.

A little more info for you to consider.....Container drainage

After my shopping spree at Brecks, I had a bunch of bare roots I needed to pot - getting a bunch of concrete work done and I can't plant till they finish, so they won't be in these permanently. I got plastic nursery pots - 7 gal I think and looked around on GW to find potting medium ideas. I went with the 5-1-1 mix, but made it 5-2-1 - more peat to retain water a little longer. Mixed in the wheel barrow - used a 3 gal bucket and it all barely fits - 5 buckets pine bark mulch ($3 @ Walmart per bag), 2 buckets peat (scored a big bale on sale for $5), and 1 bucket Perlite, plus 2 cups of Miracle Grow granules for tomatoes, and 2 cups of Lime ($3 @ WalMart - the "tone" brand). The ones I planted a few weeks ago are doing great - I put one in the ground and it had great roots on it. And the pots are not super heavy. Do need to water about every other day though, depending on sun exposure and temps. This worked for me, but I'm guessing everyone has their own method :) Good luck!!

Most of the GW recommended mixes (5-1-1 and the like) I find that they retain too little water for roses. All these recipes I suspect have been developed by and for people having problems with plant root rot and they do work in such cases. Not good for roses in pots unless one lives in an extremely wet place IMHO.

I think one shouldn't fuss too much over the substrata for roses to be temporarily kept in pots nor about any additives to be used. Just a small quantity of granural general purpose fertilizer once or may be twice for the 3-4 months or a few times watering with a water soluble fertilizer will be ok for the roses.

Btw, I would tend to shy away from limeing pot soil, or garden soil for that matter, unless I knew I had to correct an overly acidic pH. Limeing is required in the case of the 5-x-x mixes and the like because the pH of the mix is too acidic by design.

Yes I figured I'd be watering more frequently, but that's not a problem here. When I was reading about all the different mixes and voodoo, it seemed like this might encourage root development, and since I was using it for bare roots, I figured I'd take a shot at it. And it was pretty cheap to make up, and I needed to pot up like 15 bare roots! I really like it though! I wound up using it in my big pots with Hibiscus and annual on the patio too. And no, I wouldn't add lime ever, only to this stuff!

Everyone's opinions will vary and the best thing you can do is experiment a little and see what works best for you.

Wirosarian, I've read that piece and have to say that I've recently stopped putting the styrofoam packing peanuts in the bottoms of the pots. I haven't noticed any difference in how the roses do so I will not be adding them from now on.

Vasue: thanks for your advice. the soil here is somewhat sandy I believe. Not beach sandy obviously, more desert like. I'm actually new to the area so I don't know a whole lot about it. The new home is in a development which is built on land from a former mine. I'm pretty sure there has been a fair amount of fill added, but it still looks sandy with lots of little rocks. So for planting soil considerations while potted, I guess I should look for something well draining? Not really sure.