Juvenile bloom in cold Hardy varieties

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Juvenile bloom in cold Hardy varieties

Post: # 69892Post mntlover
Fri May 17, 2019 2:41 pm

I have a seedling from Therese Bugnet that is developing a bud at about 10 weeks old. It is about three inches tall, and is starting to branch out below the bud already.

Is it unusual.to bloom this early? I thought I had read that some rugosa hybrids may bloom but late in the first season. Is that correct? (Important as I have a lot of Hansa seedlings also.) My other Therese Bugnet seedlings have taken two or more seasons to bloom.

What about other Canadian varieties? I have seedlings that the pollen parent was William Baffin, many are strong growers, but none have bloomed. Is it possible they will bloom second or third season and still be repeat bloom ( like some rugosa)? Or would they all end up once blooming?

Any thoughts appreciated as I need to cull some since they all will not fit in my test bed, but need to decide which.

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Re: Juvenile bloom in cold Hardy varieties

Post: # 69893Post jbergeson
Fri May 17, 2019 4:58 pm

Very good news on a Therese Bugnet seedling showing juvenile bloom. That is a good sign that it will be a repeat bloomer.

I haven't worked much with TB, but my understanding is that a rugosa may show delayed onset of rebloom. That is a frustrating characteristic for a hybridizer, as we would love so much to cull based on whether they bloom the first year. When crossing rugosas with modern rebloomers, some of the resulting seedlings will bloom the first year, so one has to make a decision with those that do not whether to pursue the chance of delayed onset remontancy. It is particularly annoying if, for instance, you cross a rugosa like Belle Poitevine with a rose like Prairie Joy that does not always pass on remontancy. In such a case many of the seedlings that did not bloom the first year may never become rebloomers. However, if you have the resources to grow out a ton of young seedlings you could screen for first-year bloom even with such a cross. My current official strategy is to toss out any rugosa x modern seedlings that don't bloom the first year, but I've sometimes relented and planted out some of the non bloomers.

If a William Baffin seedling does not bloom as a youngster, in my opinion it will never become a reblooming rose. William Baffin can throw repeaters, though, I think. I have a seedling that's Knock Out x William Baffin that reblooms.


Larry Davis
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Re: Juvenile bloom in cold Hardy varieties

Post: # 69894Post Larry Davis
Fri May 17, 2019 7:21 pm

The only rugosa I have ever attempted to cross is Th B. The only pollen donor is R pomifera. But I think that all the offspring are actually ThB only. I feel like the Rp is inducing some kind of apomictic seed production because I never had hips form on ThB before using the R pom. (maybe 1 in 5 yr). A few years ago I grow out a bunch of seedlings and planted them in a bed. One of 20 or so survivors was reliably reblooming all last summer. Foliage very rugosa. It has a flower deeper purple than ThB and more double. Actually quite nice. so far it is only under 2 ft tall. No idea where it will go in future. This spring a number of the other seedlings, maybe 5, have had flowers. We have to wait out the year to see if they rebloom. This is their (beginning) 4th year from sprouting. 2-3 have single dark pink flowers and a foliage than isn't rugose. A couple more are still in bud stage and rugose. None of the offspring look like R pom.

So I guess to me this says that blooming at all won't often happen before a certain amount of biomass is accumulated. Probably reblooming is only available after that point if there is really a juvenile period. If you got a flower in 1st season I'd say its a really good sign. Congratulations.

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Re: Juvenile bloom in cold Hardy varieties

Post: # 69895Post donald_vancouver
Fri May 17, 2019 9:31 pm

I am finding that many of the reblooming Canadian varieties, even when crossed with other rebloomers, don't have juvenile bloom in their offspring. I agree it's a good sign that you have an F1 of Therese that has juvenile bloom.
I too am culling based on first-year bloom. If they don't have it, out they go. I just don't have the space to keep everything for three years.
Southern Gulf Islands, BC, Canada
Zone 8. Warm dry summers, cool wet winters.

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