Planting Grafted Container Roses in Cold Climates

– Posted in: How-to, Roses
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Sophy's Rose, a David Austin roseAs I mentioned to Elizabeth, I’ve been busy planting roses. I received nine bareroot roses this spring from the generous folks at David Austin Roses. Three each of three varieties. I planted the three Crown Princess Margareta soon after they arrived. But I wanted to plant the other two varieties, Gertrude Jekyll and Sophy’s Rose, in front of our porch. Since the porch was scheduled to be dismantled and rebuilt this summer, I didn’t want to plant the roses until after the work was done.

Better Late Than Never

Gertrude Jekyll, a David Austin roseSo it was that I found myself planting three Gertrude Jekyll roses on October 10th. (By the way, did you know that the British pronunciation of Jekyll is JEE-kull?) I think, under ideal circumstances, I would have planted them about a month earlier. But roses can take a light frost and keep on blooming, and their leaves persist through several hard frosts. Dan Segal, owner of The Plantsmen Nursery near Ithaca, assures me that “in fall, most plants continue to send out new roots even after the tops (stems, leaves, etc.) tire out.” I am confident that they have a better chance of making it through the winter in the ground than in their containers, and that clinches it for me. Any plant in a container needs to be two zones hardier to survive outdoors in the winter, because the roots aren’t insulated from the cold as they are when buried in the earth. And my experiments wintering over hardy perennials in my basement were not all that successful. So, in the ground they go.

Tie Up Your Roses

Tie up the rose before planting

Click for larger

First, tie your rose up. I am using baling twine but just about any twine would do. This makes the rose much easier to handle, though you can still get scratched. Next, tease out the roots and remove as much potting soil as feasible. To be honest, if you’re like me and let a few weeds take root in the pot, the first step is to remove those weeds. This made removing the potting soil easier, actually. I also used a tool meant for removing weeds from pavement cracks, sliding the blade under the roots on the bottom and prying up, then poking it into the soil in various places.
rootball of container grown rose

Tease out the roots with the tool of your choice.

I’m sure you will develop your own method. Many gardeners say just cut through the root ball in several places. Perhaps if I was doing this in the spring, I would. But I feel like these roses don’t have a heck of a lot of time to grow new roots, and the ones that I snap are enough stimulus to make more. Once I got most of the potting soil off the roots, I put each rose in a bucket of water to soak while I dug the hole.

Identify The Bud Union

bud union of grafted rose

The bud union is where the desired rose cultivar is grafted onto the rootstock

Let’s take a look at the root ball. David Austin roses are usually grafted onto a rootstock. The rootstock is typically hardier than the beautiful rose grafted onto it. So, if the grafted rose dies from the cold, you often still have a rose growing from the rootstock, only it’s not the rose you were expecting. (I have been given roses like this from less experienced gardeners, who tell me the rose has reverted to a different color.) The place where the desired rose variety is grafted to the rootstock is called the bud union or graft. Doug Green, in Tender Roses for Tough Climates, recommends planting David Austin roses with this bud union six inches below ground level. The David Austin rose company says to plant the union about four inches below ground level. When I planted my very first David Austin rose two years ago, I followed Doug’s advice. That William Shakespeare 2000 rose is doing great. This year I am following the David Austin company’s advice. If I lose all these roses, then we know we’d better stick with six inches below ground level.

But if four inches is enough, well, why dig down those extra two inches? You may think I’m being lazy, but just think about how long those roots extend below the bud union. We are talking about an eighteen-inch deep, thirty-six-inch wide hole, dug in stony clay soil by an out-of-shape middle-aged woman who needs to function well enough to cook supper the following evening. Yes, I need the exercise, but I also need to finish before nightfall. (Not to mention the break I took for the Garden Rant Cocktail Hour.) And there are other awkwardnesses involved, such as where to put the dirt that you take out of the hole if you’ve already got the wheel barrow full of compost and you don’t want to pile it on the surrounding plants or the driveway. (This particular bed is sandwiched between the porch and the driveway.) And if you garden on a slope, a flat-bottomed hole will be deeper at the uphill end of the slope, so do you measure from the uphill side of the hole, or the downhill side? Yes, I actually worry about things like that.

Three roses, three different root balls

The distance between the bud union and the end of the root mass can vary quite a bit

Since the distance between the bud union and the end of the root mass varies with each individual rose, you have some leeway in positioning them. The most important thing is to get the bud union four inches below ground level. So I put the rose with the longest roots at the deepest end, and the one with the shortest roots at the shallower end of the hole.
Three roses positioned in the planting hole

The rake handle helps me see where ground level truly is

David Austin Roses recommends digging an eighteen-inch hole regardless of climate. I am notoriously bad at judging distances, so, yes, I measure.
Measure the depth of the rose's planting hole

David Austin Roses recommends digging an 18 inch deep planting hole for their roses

Backfill

Okay, now we’ve got our roses positioned in the hole at the correct depth. We need to fill the hole back up. The current wisdom (unless it changed while I wasn’t looking) is that you want to put the native soil, unamended, back into the hole. It is believed that plants are just as lazy as people are, and if the planting hole is filled with fluffy chocolate cake-mix soil but the surrounding soil is pasty clay, the roots won’t bother to penetrate the clay, but will instead circle around and around in the easy stuff, until there’s nothing left. I tried to keep this in mind when potting them up, adding some native soil to the commercial container mix. I also loosened the soil in the bottom and sides of the planting hole before I put the roses in, so it’s more amenable to root penetration. But I do amend the original soil with compost, or what passes for compost around here.

Why? Because. Because I take big rocks out of the hole, and something has to go back in. Because I just can’t believe that a little compost will hurt, and it might do some good. Because I’m the gardener and I can if I want to. I don’t thoroughly mix the soil I took out of the hole with compost. Rather, I throw in several shovelfuls of native soil, then a shovelful or two of compost. Once there’s enough backfill to hold the shrubs in place, I water it in, enabling the soil to settle in around the roots. Then I keep repeating the process. If I suspect there are air pockets, I poke my finger in around the roots to make sure the soil is in the nooks and crannies. Then I add more soil, more compost, water again.

Now this is important. I did not fill the planting hole all the way back up. According to Doug Green (or, more properly, the 1997 edition of his book, as he has re-published it more recently as an e-book), “burying leaves and emerging buds can quickly kill a [rose] plant.” Instead, he recommends only filling the hole back up to the level of the bud union. This is what I did. Then, he says, “let the rose grow until the end of the season, then finish filling in the trench in the fall when the plant is dormant.”

Rose bud union is four inches below ground level

Bud union is four inches below ground level. The remaining soil will be shoveled in after the roses go dormant.


There are few plants I take such pains with, but I do it so I don’t have to worry about them in the future. It is a pain in the neck to stockpile the remaining soil until the shrubs are dormant, and, frankly, it is difficult to know when they have gone dormant. As I remember, the last moderate day in November, the day reserved for the last outdoor chores of the season, was the day I filled in the remaining earth around the William Shakespeare 2000. And it still had most of its leaves on it. But I was afraid the soil would freeze solid if I didn’t do it then, and I knew I wasn’t going out again until the January thaw.

Why Plant in Groups of Three?

David Austin Roses suggests planting in groups of three or more with 18″ – 24″ between plants of the same variety, giving the effect of one large bush. Since they were kind enough to provide me with three of each variety, I decided to follow their advice. Dee Nash told me that she planted her sample roses this past spring in groups of three, and they did indeed look like one big shrub.

David Austin Roses Hardy to Zone 4

This was taken from a sheet I picked up in 2007.

  • Gertrude Jekyll
  • Charlotte
  • The Mayflower
  • Crown Princess Margareta
  • Winchester Cathedral
  • Mary Rose

There are a few more hardy roses listed on their website.

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

When dealing with frost it is always best to be paranoid. In the spring never think it is too late for one more frost to come. And in the fall never think it too early.

~Rundy in Frost

6 Comments… add one

Hyra Container November 24, 2010, 5:43 am

I’m really impressed by your gardening skills, thanks for the valuable tips and guides. I’m a frequent visitor here :)

/Liz

Missy Flowers October 25, 2010, 6:25 am

I agree – great post, Kathy! Well done!

Dee @ Red Dirt Ramblings October 24, 2010, 8:36 pm

Kathy, you must work so hard to have these beauties. I’m impressed by your endeavor. Here, I can just plant and not worry too much about it getting too cold. I’ve enjoyed my summer roses and hope they continue to do well and not get rose rosette.~~Dee

Kathy Purdy October 26, 2010, 8:31 am

We often have to dig deeper because of the cold. Just try digging post holes below the frost line! I hope no more roses succumb to rose rosette in your garden.

allanbecker-gardenguru October 24, 2010, 7:54 pm

Great post, Kathy!

Kathy Purdy October 26, 2010, 8:31 am

Thank you, Allan. Do you grow many roses in your garden?

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