How much cold can R. bracteata take?

Some of you know that my area experienced a severe cold snap in December, during which night temps dropped as low as 7F for several nights. I have a large plant of R. bracteata growing in the floor of one of the greenhouses (unheated, but sealed) where it is at least somewhat protected. Many other tender roses like my Teas survive without damage in the same greenhouse. The R. bracteata was still fully leafed out at the time the cold hit. Over the past 5 weeks or so, the foliage has slowly turned grey, then brownish and the canes are going limp. I get the impression from cutting a few canes to investigate, that water is no longer flowing through these canes: they are slowly desiccating. I strongly suspect most of the canes of this plant are dead. What is your experience? Should I leave the plant intact or go ahead and cut most of it down? The corner it occupies is getting very tangled with R. bracteata taking up more of the space than I care to allot it, so having an excuse to cut it back hard isn’t a bad thing, in that regard.

As an interesting side note, a large plant of Moore’s ‘Pink Clouds’ rootstock growing only a few feet away was still actively growing, with soft shoot tips and new foliage, and yet it suffered no damage whatsoever. The foliage didn’t even get burned! I was so surprised by this.

Paul

Hi Paul, I’m not surprised at Pink Clouds. It’s parents are quite cold tolerant. The only experience I have with cold and Bracteata was the freeze we had several years ago which took temps down to that range for four days with a cold, dry wind. Sheltered in a walled garden, and in a pot, it didn’t seem to suffer anything.

G’Day Paul… here, temperatures don’t get that low… -7 would be the worst we get (Celcius). However, my bracteata arrived during the low of winter here and there was no top growth at all (it had been defoliated) but when I unwrapped the body-bag it came in the roots had begun to make adventitious shoots (which I was able to snip off and pot up and pass around to friends later in the season). Robert has explained this to me before, as did someone else… persistant roots they called it… so the roots are extraordinarily tough so I wouldn’t be the least bit worried about cutting it back. I have found with mine that once you cut it back, or it experiences any form of set-back (like drought… it nearly died on me because I planted it in a paddock and then it got very dry and hot) it takes a really long time to come back and even start flowering again (mine has taken nearly 12 months and now I have about three flowers beginning to form towards the end of our pollinating season)… so if you had plans to use it in crosses this coming season you might want to leave it to see if any canes did make it and once the growing season starts again then lop off the obviously dead ones and hope to get flowers. Mine is still relatively young so having a big established root system to kick start it again might make things different…

Thanks for the feedback. I think I’ll leave it intact and just see what comes. I can live with the octopus in the corner of the greenhouse for another couple months!

Paul,

I wonder if yours had lead a too pampered lifestyle?

My two live at the bottom of our mountain top, one in acidic red clay and the other in old river sandyloam on top of a chert pavement about a foot down. Neither is ever watered (or even fertilized). Temps down there are five degrees F colder than up by the house. It’s not a great place for roses, which makes it interesting.

Mine survived temps below zero F about eight years ago. Since then they have survived that very late Easter Freeze when every rose in the garden was leafed out AND budded out and it suffered with the rest. It also bounced back.

Mine are not from a commercial source but were sent me from Texas where it was and is a weed. I expect mine came from a clump from a seedling and I wonder if that has managed to avoid some genetic problems…as my first one was from a nursery, was grown in a protected spot up by our house (it being sotospeak tender) and it was no where as vigorous.

To give you my take on your question, it’s not so much ‘how much cold’ as what the rose has had affecting it before the cold comes.

Ann

Ann said,

“Mine are not from a commercial source but were sent me from Texas where it was and is a weed”

It would be interesting to compare the two.

Mine was from Sequoia. I raised what I assumed to be a selfed seedling from it and gave it to Cliff Orent.

I note Cliff now offers R. bracteata and have to assume it is the seedling I shared about 5 years ago. I noted phenotypic differences from the Moore version.

Then too we have to wonder what version Viru works with?

I have a feeling there is significant variation within the species.

"Then too we have to wonder what version Viru works with?

I have a feeling there is significant variation within the species."

Why wouldn’t there be? There are within every other “species”. Ralph collected 11 different variations of Minutifolia and that is from one, small group of “species plants” occurring in only two major places. If that could demonstrate 11 obvious variations without outside intervention and presumably without hybridization, why should anyone believe there actually IS one “true” type for any “species”? I believe any wild plant which Nature didn’t program in fairly widely varying possibilities would be dooomed to fairly easy extinction.

Some time ago, there was a group of individuals involved with determining what should and shouldn’t be considered normal for each species. I followed them for a little while until it became too tedious for me. I consider “species” as I consider any other organism, including Humans, as a large collection of possibly expressed characteristics. As long as it quacks, has fairly webbed feet, takes to water like one and fairly resembles a duck, to ME it IS a duck. Yes, I am a pragmatic.

I agree.

When I lived in Lubbock, TX (USDA 7a, with occasional USDA 6a winters), I planted several bracteata seedlings outdoors. They did not grow large (way too dry to suit them), but they did survive for many years until the drought took them. The seeds had been gathered near Richmond, TX.

Here in Charleston, WV (USDA 6b, more or less), the bracteata that I got from Kim in 2002 has survived, but the winters mostly keep it from taking over. I had it in a pot, but let it grow through into the soil, and left it outdoors in spite of its reputation for tenderness. It got zapped by the cold 2 years ago, but in mid summer a sprout emerged from beneath the pot, and it was sprawling about 4 feet in every direction this past year. It also had a few flowers on wood from the year before.

I also have a plant grown from clinophylla x bracteata seeds sent by Viru, That too has survived outdoors, and has a fair number of flowers every year, mostly from old canes near the ground. The canes do freeze back to about 18 inches.

Anyway, Paul, you’ll probably get a few flowers, and I’m pretty sure your plant will survive.

Hi Paul. I gave a R. bract. to my friend up here in the Tualatin Valley. It’s about 10 years old and survived each winter just fine. He lives next to the Tualitan River, too, so it obviously can survive water-logged soil, too, lol. My only comment about it is that it is painful to play with :stuck_out_tongue: The flowers are weird for a rose. The leaves look like tiny little shields. I think it can be useful in breeding, but definitely not my personal taste.

Thank you everyone, for your ideas and opinions. I am inclined to agree with you in that it will survive, its just a matter of how much damage it sustained. Usually the greenhouse provides considerable protection during freeze events, even though it gets almost as cold in there as it is outside. I agree with Ann about the state of the plant when the freeze occurs, but as I said, many plants in the same area were still actively growing (bracteata had stopped growing but was still leafed out) and they suffered no damage at all.

The R. bracteata looks really sad and I want to clean it up, but I will wait to see how it does. Many other roses are leafing out now, but it shows no signs of growth yet. I’ll wait another month and then re-evaluate it.

Thanks!

Paul

PS: I have two plants of R. clinophylla raised from seed distributed by Gene Waering years ago. One is planted in the open garden and one is in a large container in the main breeding house. Every year the garden plant is killed to the ground and doesn’t start growth till June. That plant rarely blooms because it is always struggling to recover from the damage. The greenhouse plant rarely suffers much damage from the freezes we get most Winters. However, this year all top growth on this specimen was definitely killed by the freeze. I am, in fact, concerned that it may be dead, period. A shame, because I don’t have a backup plant. I do have three seedlings grown from it that I am using in breeding now, (derived from Moore’s 0-47-19) and two of those are clearly far more freeze tolerant than the species is: they suffered no significant damage. One of these, however, appears to have lost 80% of its wood to freeze damage. Curiously, it is the white one that most closely resembles its species parent. The hardier two are pink and look more like the other parent. See link.

Link: www.helpmefind.com/rose/l.php?l=2.61316

Paul,

Just because a stem looks dead may not mean it’s totally dead. (Snicker now)

In my species bed are plants of R. laevigata. Well, there were two from the same parent plant in south Georgia. One is gone after drought. The other looked badly damaged after that very late spring freeze two years ago. The one and two year old canes had black streaks on them. But there was green in between the black. I was surprised when the nodes supported by the green stem segments started growing. Those green stem bits put out classic laterals and they live to this day. And they bloom and set hip laden hips.

Something in the laevigata genes separates the vascular tissue and isolates the unhealthy parts from the still alive parts.

So there may be something in your plants that’s unlike some of the Eurasian sorts

Good point Ann. The plant looks like it is in serious distress, but it may prove me wrong. I’ll leave it alone for now. Thanks.

Paul, if you lose R. clinophylla, I can provide you with a plant or with cuttings from a cutting-grown plant from Robert’s plant.

Thanks Cass! I’ll let you know if I need to replace it.

Cass, how large did that clinophylla get for you?

It was enormous here in a short time.

I remember you saying that it repeats into Winter where you are. That would definitely slow it down.

No doubt it was the most vigorous of the seedlings I grew out from the seed Gene distributed.

Robert, is that the same one that you gave me? I still have two, but have kept one in a very small pot and the other is in a #7 squat. It is vigorous and I keep it for the possibility of breeding tropical type roses, but haven’t done anything with it yet.

Jim Sproul

Hi Jim, yes, the same one. Didn’t I bring you cuttings?

I think I remember you said you were putting them in your mist set up. I remember you showing it to me.

I also gave Sequoia cuttings but they were never stuck.

Robert, my Clinophylla was grown from your cuttings. It is not in the least out of control. It’s 5-6 feet tall and rather narrow and upright. It blooms continuously from mid-spring (some time in May) until it’s stung by frost in December. We haven’t had any serious freezes since I planted it. It probably gets much less water than it would like during the growing season and more than it likes during the cool winter.

Interesting Cass.

I’m guessing the heat here made clinophylla go crazy vegetatively. My specimen got the run off from my propagation area. That also might account for the exuberant growth.

This said, I think the most vigorous species rose I have ever grown is now R. lyellii. Without coddling it exceeded 20 feet in its first season.

As you know botanically it’s closely allied to clinophylla.

You said you were able to root one of the cuttings I brought North last year?

How is it doing?

Link: www.helpmefind.com/gardening/l.php?l=2.44938&tab=1