Stay with zone 4a as that's what you are. Hardiness zones are listed by annual average "minimum" temps. With yours getting to minus 27, that's the minimum temp you have to plan for. To do otherwise could be costly and require extensive winterizing on plants not rated for your minimum temps.
I try to err on the side of caution.

USDA Hardiness Zones and Average Annual Minimum Temperature Range

Zone Fahrenheit Celsius Example Cities
1 Below -50 F Below -45.6 C Fairbanks, Alaska; Resolute, Northwest Territories (Canada)
2a -50 to -45 F -42.8 to -45.5 C Prudhoe Bay, Alaska; Flin Flon, Manitoba (Canada)
2b -45 to -40 F -40.0 to -42.7 C Unalakleet, Alaska; Pinecreek, Minnesota
3a -40 to -35 F -37.3 to -39.9 C International Falls, Minnesota; St. Michael, Alaska

3b -35 to -30 F -34.5 to -37.2 C Tomahawk, Wisconsin; Sidney, Montana

4a -30 to -25 F -31.7 to -34.4 C Minneapolis/St.Paul, Minnesota; Lewistown, Montana
4b -25 to -20 F -28.9 to -31.6 C Northwood, Iowa; Nebraska
5a -20 to -15 F -26.2 to -28.8 C Des Moines, Iowa; Illinois

5b -15 to -10 F -23.4 to -26.1 C Columbia, Missouri; Mansfield, Pennsylvania
6a -10 to -5 F -20.6 to -23.3 C St. Louis, Missouri; Lebanon, Pennsylvania
6b -5 to 0 F -17.8 to -20.5 C McMinnville, Tennessee; Branson, Missouri
7a 0 to 5 F -15.0 to -17.7 C Oklahoma City, Oklahoma; South Boston, Virginia
7b 5 to 10 F -12.3 to -14.9 C Little Rock, Arkansas; Griffin, Georgia
8a 10 to 15 F -9.5 to -12.2 C Tifton, Georgia; Dallas, Texas

8b 15 to 20 F -6.7 to -9.4 C Austin, Texas; Gainesville, Florida
9a 20 to 25 F -3.9 to -6.6 C Houston, Texas; St. Augustine, Florida
9b 25 to 30 F -1.2 to -3.8 C Brownsville, Texas; Fort Pierce, Florida
10a 30 to 35 F 1.6 to -1.1 C Naples, Florida; Victorville, California
10b 35 to 40 F 4.4 to 1.7 C Miami, Florida; Coral Gables, Florida
11 above 40 F above 4.5 C Honolulu, Hawaii; Mazatlan, Mexico

The USDA hardiness zone maps are averages. They deliberately don't account for microclimates, and that particular detail matters even more in the West, with its significantly more dramatic elevation differences, than it does in the East.

karl is right.

Thank you. I've been looking for roses that are reliable to zone 4, but thought I'd better check.

I know a lot of climbers have winter die-back in my zone, but are there any that are pink? William Baffin is a little too dark, I was hoping for something more like New Dawn. I have a Climbing Cecile Brunner that may or may not make it through the winter, but it's up against the house, so I'm hopeful.

The kitchen garden is on the west side of the house, against a lilac hedge, which blocks a lot of wind. The arbor would be 20' from the hedge and should gets full sun all day.

I recently ordered Gartendirecktor Otto Linne for a different location. I've seen that as a climber in warmer climates, but I don't know if it would be in my area. It's supposed to be hardy to zone 4. If that would climb, that would be nice. Any other rose suggestions?

What kind of a climber are you looking for (in terms of growth habit & size, rather than bloom)?

I would like a rose for the arches in the kitchen garden that won't take up too much room. I'd like one that gets at least 8' to 10' tall in that area. It would also be nice if it was a reblooming rose, but in other areas, once-blooming would be fine.

In other parts of the garden, I don't mind if they're a little bigger at the bottom. (I've never grown climbing roses, so maybe pruning them keeps them from being such large shrubs at the bottom.)

I don't mind a rose that gets taller than 10' tall, but with possible winter die-back, I don't want a rose I think will be that tall and never gets over 5'.

Roses are my first choice for climbers, not because they necessarily fit my space, but because they're beautiful and non-toxic. I have cats and kids running around in the garden, and I especially have to make sure toxic plants don't find their way into the horse pasture. I love fragrant roses, especially the ones that smell like roses, not lemon, grass, etc.

I am planning to go to Northland Rosarium this summer, so I'm hoping to get some ideas of what might do well in my area. They should be within one zone of my place, so I'm hoping to find some nice possibilities.

White roses are pretty, but tend to brown out with our hot summers, unless they're in shade part of the day...as do really pale pink. I like red, pink, lavender, crimson, even yellow or peach (like Alchemist) in the right part of the garden. I also like the look of ramblers and even roses with single blossoms, since they look old-fashioned. I would love to have more arbors in the yard (for shade) if I could find cimbing roses that would do well in my area. I don't suppose there's a tall alba I could tie up to the arbor? :)

I grow Compassion and Clair Matin. Both get dieback but grow back quickly each spring after being pruned. They both repeat and are good bloomers.
Unfortunately for us in colder growing zones, there are very few climbers that stay green to the tips or require very little pruning.
aside from Quadra (red) and New Dawn (White/pink blush) all mine get quite a bit of dieback.
I accept this penality for living in a cold winter zone. Not much else I can do except move.
Because modern roses bloom on new wood, I get a great bloom each year by having to prune back so much. After the roots mature in 3-4 years the plants recover quickly and grow quite large each year.
I've learned to live with what I can successfully grow. If a modern cold hardy climbing rose comes along, I'm sure we'll hear about it.
Meanwhile I take what I can get. These are not my pictures. They are taken from online mail order catalogs and are as close to the expected color as I can remember.

Compassion
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Clair Matin
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Thank you Karl. I saw Clair Matin on the Heirloom Roses webiste and thought it was beautiful, but was afraid it would die back too far. Compassion is pretty too. It's good to know they might do well here. New Dawn would be fine too. I like the pictures I've seen of it and it's supposed to do well in zone 4. (I can plant it where it will get afternoon shade.)

Have you tried Viking Queen or Alchemist?

Also, has anyone tried Darlow's Enigma? It's a beautiful rose and one of the only white climbing roses I really want to try. Maybe it's the small size and the gold stamens. It looks like bee heaven :)

It's a shrub. It's also reportedly not totally hardy in Minnesota.

Though I have no first hand experience with how hardy they truly are (how low can you go?) the early setigera ramblers are probably worth investigating. Then there are things like Lilian Gibson, which I saw once, and maybe Boursaults.

I have Viking Queen also. Keep in mind these will die back quite a bit. After spring pruning they come back strong.
It's just a fact we have to put up with if we wish to grow climbing roses in our zones.
You can chose to forgo them or put up with the dieback.
I chose the latter so I can enjoy for 5 months. Part of the pleasure is watching them come back to life each spring.
I grow Darlow's Enigma too. It is hardier than the others but not quite as hardy as Quadra. The flowers are tiny singles and grow in clusters. It reminds me a lot of multiflora but repeats and is not so wild as multiflora. I had multiflora for a number of years but it tried to take over a large portion of my back yard. Not so bad for a repeater but not for a once bloomer. Once established, multiflora can create a large thicket and will grow back almost as fast as it's cut back.
My Viking Queen is in partial shade and still rather young. Perhaps as it gets older it will be a little more cane hardy?

I don't mind if the roses die back, as long as they have time to grow large enough to bloom. I've heard that some climbers die to the ground and just get tall enough to put out blossoms when it's the end of the season.

As long as they bloom and are tall enough to look somewhat like a climber in August, I'm happy :)

I can't offer personal experience with it, but I have been intrigued by a relatively uncommon climber known as Isabella Skinner (also sometimes sold as "Victorian Memory"). HMF indicates it's hardy into zone 2, and was bred by a Canadian rosarian who deliberately included in its breeding a wild Siberian (I think??) rose so that what he got would be hardy in Canada.

It's a rebloomer, and if you search the Garden Web forums using "Isabella Skinner" you'll find about a dozen threads where it's mentioned at least once by someone or other. The medium pink flowers are double, but a bit more lax than you'll find in something like New Dawn, so if you really want a climber with perfectly double blooms you need to look elsewhere.

What I've read of it here from people who have grown it is that it isn't suitable for climbing. Apparently while it can get very big (10'+) in the right situation its growth habit is too "shrubby" to pass as a climber.

The name of the species he used while breeding Isabella Skinner is Rosa laxa. I just checked the USDA's plant database and learned it's native to central Asia, including western Siberia, a few of the central Asian Turkic countries (including Kazakhstan), Mongolia, and western China (Xinjiang).

Holy cow!! That's a gorgeous rose!!! Zone 2!!!! Fragrant!!!! But York Rose - you say it won't put it's growth into upwards, but more sideways!!! - ARRRGGHH!!!!

Carol

Of my climbers that dieback, all are blooming by the middle of June at the latest and are climbers again by mid July. I have over 30 climbers with most requiring severe pruning.
Following are my climbers with a couple more that grow tall enough to be called climbers. I've had most for seven years. BTW, they are all own root.
Clair Matin
Autumn Sunset
William Baffin
Roseraie de LÂHay
Fourth of July
Aloha
Westerland
King Tut
Green Ice
New Dawn
Red Cascade
Red Wand
Emily Carr
Berries & Cream
Handel
Jeanne LaJoie
Butterscotch
Seven Sisters
Louise Odier
Rosalie Coral
Leverkusen
Compassion
Goldener Olymp
Coral Dawn
Berlin
Dortman
PaulÂs Himalayan Musk
Viking Queen
Celsiana
Dublin Bay
Quadra
Gartendirektor Otto Linne
Zephirine Drouhin
HarrisonÂs Yellow
Veriegata de Bologna
Ramblin Red
City of York
PeleÂ

I have City of York. It's beautiful when it's in bloom, but it's too vigorous for this yard, and I intend to replace it once I have the $$ (& permission from the other condo owners). It's too vigorous for this yard (relatively upright, arching basal canes that easily get 10'+ long), dies back almost not at all in my zone 6 situation, only blooms in June, and is viciously thorny!! They're huge!

(Oh yes. Anyone reading this needs to understand that I have it growing along a fence that's only 3' high..... The canes are arching out, reaching out to scratch the condo owners' cars on the other side of the fence! :) It really is a vigorous, big climber with large, thick, sharp thorns. If I had the right location for it I would love it, but I don't have the right location here. Next to it along the fence is New Dawn/Dr. Van Fleet (not sure yet which it is, although I suspect it's Dr. Van Fleet), and it's much more upright and vigorous than New Dawn/Dr. Van Fleet. City of York also has yet to become infected with powdery mildew, while the other one (whatever it is) already has in some late summers.)

Yikes, -27 sounds very brrr cold.

John Davis is a superb rose that repeats bloom well, gets orangey red fall color on the leaves, forms little round orange hips, and then the canes turn red over the winter. Look at this picture by Daisy in Mi on a linked thread. "Daisy's John Davis" . I don't grow John Cabot, but that one looks gorgeous too. She notes that her JD mildews. My JD has never had mildew in my semi-arid climate.

That Isabella Skinner/Victorian Memory is one I've been wanting since seeing Anne Cecilia's pictures on HMF. Must first make some room though.

Darlow's Enigma is also a beautiful and fragrant rose. Also disease free and great repeat. Mine is covered in masses of litte red hips right now. I have seen it grown as a climber on a south wall round these parts. Whether it could get up and over an arbor (especially in zone 4), I don't know. Mine is grown as a lax shrub. I'll link to a thread w/ Cnetter's DE in zone 5.

Karl that is quite a list. I'd love to see photos. It must be a spectacular sight.

Here is a link that might be useful: Thread w/ Darlow's Enigma

Barb- Thanks for the thread. Darlow's Enigma looks beautiful as a shrub or a climber. Neat idea to grow all the roses and clematis together...very pretty!

While I have some space for shrub roses in front of a huge lilac hedge, I'm trying to find the best climber for an entrance into my kitchen garden. I'm trying to find a wooden or metal arbor, about five or six feet wide and about three feet deep. I have a second entrance, so I don't have to get into the garden that way all the time, just in case the roses get a little large in later summer :) I would like to find something fairly well-mannered that is more of a pink or lavender, which may be difficult with my zone limitations. I like Clair Matin, since it's a nice color and would go well with the other flowers. I plan to put some coneflowers, coreopsis, and other perennials along the front, on either side of the arbor with some annuals mixed in. I'm really trying to bring the bees and other beneficials into the garden. I also plan to include some Marie Bugnet rugosas and lavender with some other herbs in the center garden. Any other suggestions?

I have 20 climbers and more that have departed over the years. Only one has proven to be hardy and vigorous - Illusion. It has wonderful foliage and hardy in my 5a. It's flowers are also great a satifying deep red with good form. It was very slow to get going like 7 years.

New Dawn turned out to be the Doctor and is hardy, very big and flooms well in season.A great rose is Baltimore Belle. Extremely vigorous, tip hardy and blooms profusely in season with wonderful fragrance. Something to look forward to every June. Very big.

Oh and Alchymist is big, hardy and has wonderful flowers. A number of my other climbers hopefully will also get their stride and become like Illusion. Roseraium Uetersen has great flowers but remains small. Westerland same and Salita is a nice orangey flower.

Spring 2009 climber pictures. First flush after all were severely spring pruned. All are much larger in July.

New Dawn
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Louise Odier
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Leverkusen
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Goldener Olymp
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Compassion
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William Baffin
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John Cabot (lost due to RRD)
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Variegata di Bologna (first flush after severe spring pruning. Gets much longer canes as season progresses)
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Karl- Beautiful photos! I'm leaning towards New Dawn but have heard the thorns can be vicious. Would this keep it from being a good rose on an arch, or just mean I need to wear big gloves when I prune it?

Thanks again for all the info :)

Those were all first bloom and after severe spring pruning so some are really small.
Don't know about New Dawn on an arch. As you can see mine is on a fence and is pruned only in the spring unless a cane grows into the yard. It's then pruned back or the lawn mower cuts it back.
I go through a few pair of gloves each season.

Karl, I'm very interested in variegata di bolgna, I purchased it last year and was unsure of its diease resistance and left it in its pot to see how it preformed.
Does it rebloom for you could you tell me more.

After looking at some internet nursery sites I found Golden Showers. Does anyone grow this and would it be a good climber for an arch arbor? It says hardy to at least zone 4 and nearly thornless.

Variegata di Bolgna mildews if you sneeze close to it. In high humidity or wet weather it can get blackspot and drop it's leaves. It blooms well for me during the first flush after severly pruning in spring. Only occassionally will I get more blooms later in the season. I keep it as it's vigorous and I like the flowers.
In late summer when it mildews badly, I cut it back.

Thats been my experience with VdB in the pot....Thnx 4 your response.......Mark

Also wondering, has anyone had success with William Lobb? I just found this on the Old Garden Roses and Beyond website. It's supposed to be hardy to zone 5, thorny and once blooming....but it's also good for arbors and pillars, has a strong old rose fragrance (my favorite) and it's purple! Although it's a moss, it looks like a gallica rose in this picture and I love purple :)

Is there anyway I could "baby" this and have it do well in my area? I'd be willing to winter-protect a rose this pretty, even if it did only bloom for a short period of time. Maybe put a clematis on the arbor with it?

Golden Showers is not hardy in Z4 let alone mine here in z5. A rose I tried to grow based on my experience with it in S. CA (my former garden). It died the first year! You have to be careful with zone ratings from some sources!

Jim- Good to know about Golden Showers.

I decided to get one William Lobb to go with my two Fantin Latour roses. I suspect that it might not grow as tall as they say on the website, in my colder climate. In this location it's okay it it's just a big beautiful shrub.

Thank you all for your input. I was leaning towards New Dawn for the kitchen garden arbor, but was afraid it might be too exuberant. Finally decided to zone push a little and ordered two Lavender Lassie roses that should arrive early next June. They'll be own root and the arbor will be in one of the most protected locations we have, so I'll keep my fingers crossed :)

I love the idea of New Dawn roses with purple clematis, so I'm going to put an arbor over the small seating area in the garden, opposite the entrance arch. It will be wider and give the New Dawn more room to grow. Thank you again for all the ideas and beautiful pictures!

Not that I recommend you purchase from them ($$$$$$$$!), but White Flower Farm specifically offers for sale the combination of New Dawn with the clematis Etoile Violette.

Thank you. Etoile Violette is beautiful and should go very well with New Dawn :)

ND/The Doctor is a very big rose with thick stiff canes. You might keep that in mind when planting it around an arbor. Unless there is plenty of room.

Lavender Lass I hope you can show us pictures someday, your ideas sound lovely, best of luck with them!
roseberri

Viking Queen is one of the hardiest roses I grow. She is healthy and almost always in bloom. One of my all time favorite roses.

Valerie

Thank you Karl for posting your pictures. They are beautiful. I especially like William Baffin and John Cabot. Sorry to hear about your John Cabot. I have Louise Odier too and it responds well to wrapping the canes. Yours is so pretty.

Good luck Lavender Lass with your choices. It sounds like a pretty combination.