Yes, you should find some way to protect the grafts for winter. Sinking them below the ground would be the best method. If they are outside exposed to the elements they shouldn't need watering. If they are under any covering that will prevent rain or snow from getting to them then yes, you will need to water them at least once a month all winter. Rooted cuttings will produce bigger plants faster for budding to than seedlings will. Rooted cuttings should be large enough to graft to in a year, I would think. Seedlings would probably take a few years to grow large enough to graft to. The root stock will definitely affect the size of the grafted plant but it should not have any affect on the color or fragrance. The purpose of grafting a rose to root stock is to make it more vigorous. That is why certain roses have traditionally been used as root stocks. They are very vigorous growers on their own roots. Grafting other varieties to those roots makes the other varieties grow stronger and faster too. You could heavily mulch the air layered roses with soil or any type of wood mulch for this winter. That should protect the roots which is the most important part to protect.

Meredith has some good advice. It might be easier to use what they call the "layering" method to root a cane and then cut it off. You'll have a much better success rate because the mother plant will still be feeding the cane while the section that's under the soil will put out roots. I recommend what Meredith says. Jerri has some great advice too, but you'd have to dig up the rose or build a raised area around it in order to get it deeper into the ground once its planted. If the rose is newly planted and sill easy to move (has not yet set out delicate feeder roots, within a week) you can do that. If not, try rooting it using the layering method above.

I really have mixed feedback on this issue. I totally agree that the robust growers in cold zones do fine on their own roots and you don't have to worry about suckers from the graft. Too robust growers (like gallicas) can be better grafted so that you can plant the graft ABOVE the soil (only) for those super-hardy roses and avoid the gallica taking over the garden bed. I also agree that grafted roses of the wimpier varieties of HTs and floris are more robust in their first year or two and tend to grow bushy faster than own root versions of those plants. However, I've recently started to experience the down side of grafted HTs in a cold climate. First of all, virtually all of the grafted HTs and floris that I've planted with the graft properly buried have gone own root over time if they've survived. For instance, I bought In the Mood grafted from a local nursery and it was fabulous and bushy in its first year. The second year and for every year after that, it was a knee high one-cane wonder until it finally gave up the ghost and died after about 6 years. The same process has been happening more gradually with my grafted Savoy Hotel. It was lush (maybe 4.5' by 4.5') and incredible in its first year or two, ranking in my top 20 of roses. Every year since then it has declined and come back from the winter more slowly. By August this year, my plant in optimum sun and soil conditions has just now reached almost 3 feet with 3 canes on it and a couple of blooms here and there for the first time all season (nothing at all in June). Here's a contrast picture to show that effect - this is 2013 in June for Savoy Hotel at its full 4.5'x4.5' glory. Savoy Hotel is at the bottom right corner keeping up with Madame Isaac Periere in the back of it with no trouble. Granted, this was a particularly good rose year, but you can see the relative sizes. Now just one year later in 2014, here's Savoy Hotel in front of MIP (bottom center) also in June, and this was an average rose year for me. It's too late for MIP on the shepherd's hook to be blooming, but you can see MIP's height by the purple clematis. Notice that she's now in 2014 only 3' high and has about 4 blooms every couple of weeks. She has declined from that since, even though she's still a very nice rose. I don't have any more recent bush pictures for her since I only get the scattered blooms any more, and only late in the season to boot. One other effect I'm seeing in my older grafted roses this spring in particular is graft failure for a lot of my well-established roses with the graft well buried. Even under the soil, it seems like a grafted rose starts running out of places to grow new basal shoots after a while. For instance, this spring I lost an 8 year old Dream Come True (the tall rose at the left of the first picture) for no good reason that I could see, and it was a mild winter. Sure, you see pictures of 50 year old grafted HTs in warm climates, but those are warm climates. I suspect that if we have a 50 year old HT rose in cold climates that started out grafted and is still alive, it has gone own root in that time and is a robust rose on its own roots. My reluctant conclusions are that if a rose is going to be a wimp, it will reach that state on its own whether own root or grafted. If I get an own root HT rose through its first winter it will increase in size to its sustainable height and vigor and more or less stay there for the duration. If I get a grafted HT rose through its first winter, it will decrease in size to its sustainable height and vigor and stay there till the graft fails or it goes completely own root. There are only a few roses where I think the graft did give the rose a little boost in survival over that first winter, Memorial Day and Oklahoma come to mind, but for the most part I don't think it buys me anything in either survivability or vigor after the first year. That's why I tend to grow my HTs and floris on their own roots. I want to know the long-term height it's really going to be in its early years, I get reliable winter survival of the original rose from own roots if they get to a good size in their first year, and I don't have to dig up a massive root system when it dies or deal with suckers. Just my two cents Cynthia

R. Multiflora is hardy to zone 4b, and Dr.Huey-rootstock is hardy to zone 6b. Dr.Huey-roostock can live forever in my zone 5 since its roots is at the end of a long-stick (1 foot deep), so it can survive deep underground while the upper-own-root dies. The temp. at DEEP underground is 32 F, while the above temp. is -20 F in my zone 5a. The secret of Dr.Huey's living forever is its roots are at the end of a long stick to be at 32 F underground. I saw only one multiflora shoot appearing at local library, versus countless Dr.Huey-taking over. Leaves are acidic when not fully decomposed, so I consider that peat (Peat forms when dead plants are not fully decomposed). Once time I buried a bunch of leaves underground when I fixed the planting hole of Wise Portia. IT GOT WORSE !! I dug that up and the leaves turned into pitch-black & acidic peat. Wise Portia as own-root hates it (it likes alkaline with dark-green leaves). Multiflora-roostock can take acidic leaves on top better than grafted-on-Dr.Huey or own-roots. Multiflora-species thrive in high-rain & acidic soil. But Dr.Huey was bred in dry & alkaline CA. Back in 1998 I winter-protected a dozen hybrid-teas (grafted on Dr.Huey) with acidic maple leaves (not decomposed to neutral pH). They all got black canker & died through the winter. But my neighbor's dozen hybrid-teas (grafted-on-Dr.Huey) were winterized with dry & alkaline wood-chips and they survived winter great. Own-roots absolutely hate acidic leaves on top when their roots mature to be chunky & woody like Dr.Huey. When I winterized 10th-year-own-root Golden Celebration with leaves, it was only 4" tall in spring & gave me 4 lousy blooms for spring flush. So this 11th-year winter, I switched to DRY & ALKALINE wood-chips, and Golden Celebration had over 1 foot of green cane, with 20+ blooms for spring flush (in only 4 hrs. of sun). Multiflora-rootstock prefers loamy soil since it's a cluster root (spaghetti strands), versus big-fat & woody chunky Dr.Huey for dense & thick clay. Multiflora-rootstock declines in my salty & dense & alkaline clay. Dense clay need a thicker-stick like Dr.Huey to push through. Here in rock-hard & dense alkaline clay (similar to CA), Dr.Huey-rootstock is the choice but folks plant it so deep that Dr. Huey lives forever.