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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: Rhododendron rex
I'm surprised there an arboreum hardy enough for NS. When I was in college I called the Waldmans of Roslyn Nursery to ask them about R. arboreum - it was the first rhododendron I'd wanted to grow as a teenager. They said they'd tried various forms and eventually a cold enough winter always came along and would kill it off. Of course, there were some really cold winters back then, from the late 70s to 1994.
The BVT X arboreum cross has a superb truss! How lucky to get that bicolor effect. Are you able to send cuttings to the US to be rooted?
Last edited by davidmdzn7 on Tue Dec 19, 2017 4:12 am, edited 1 time in total.
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Sat Jan 28, 2017 5:13 pm |
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johnw
Joined: Sun Mar 24, 2013 2:37 pm Posts: 240 Location: Halifax, NS
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Re: Rhododendron rex
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Sat Jan 28, 2017 6:38 pm |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: Rhododendron rex
Wow it's even more impressive it was (?) in Toronto, which I assume has a more continental climate than NS. Hotter summers, colder winters. Must have been quite tall after 35+ years? Recent injury is not consistent with patterns of winters, something else had to change. 85 and 94 were way colder than anything recent so it apparently survived those. It's tragic if it's lost for good.
Anyhow it's proof primary hybrids of arboreum can be quite hardy, related to an argument, sorta, I had with mainegrower on gardenweb. It seems many such hybrids (but not all) end up closer to the hardiness of the hardy parent. Like one that has grown to 16' in Ohio. OTOH, my R. broughtonii, only bought for experimental use as a rootstock and probably going to be de-accessioned soon (color and floral effect very unappealing) was slightly burnt in the "polar winter" where other far more attractive exotic hybrids like 'Leo', 'Captain Jack', etc. were uninjured.
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Sat Jan 28, 2017 7:42 pm |
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johnw
Joined: Sun Mar 24, 2013 2:37 pm Posts: 240 Location: Halifax, NS
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Re: Rhododendron rex
Yes Toronto is hot as hell in the summer and worse, humid as well. It gets colder there than here in coastal NS but the winter humidity there is low. I saw the plant in 2011 - it's second year of flowering - and it had blown some pips in every bud, I think the low was around -5F to -10F. In 2014 it got scorched between around -15F and dropped a number of leaves - that was extended cold, see pix.
The plant after all those years was only about 6-7ft. In the same amount of time I'd expect it to be 2 to 3 times bigger on the east coast; I guess one may assume it froze back a few times. Snow may have saved it some years.
In my experience with sp x sp crosses the hybrid is halfway between in hardiness; with hybrids who knows. So brachy at -40F and ficto at 0F would make my hybrid hardy to -20F, I'd say -10F might be bottom for buds though. My brachyrex x rex I hope for -5F buds.
Apologies for the Fahrenheit.
-40F = 40C 0F =- -17C -5F = -20C -15F = -26c
Last edited by johnw on Sun Jan 29, 2017 1:27 am, edited 1 time in total.
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Sat Jan 28, 2017 11:27 pm |
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Tim B
Joined: Wed Feb 13, 2013 11:56 pm Posts: 417 Location: Seekonk, Massachusetts USA, USDA zone 6b
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Re: Rhododendron rex
David,
The last two winters have caused more damage to my plants than ever before. My 6 foot (2m) tall Aucuba japonica died and I lost several Yucca gloriosa's above the snow line (these have never seen damage before). Feb 2015 may have been the coldest since records started (at Providence). I think the weather station recorded 6 nights below 0F (-18 C) in February (another record) and every day was below 'normal'. 2016 was the knockout punch with lows of -6F and -13F. I'm colder than Providence too.
Taunton is just north of me and recorded 11 nights below 0F.
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Sun Jan 29, 2017 12:30 am |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: Rhododendron rex
Thanks Tim, I guess I wasn't taking into account that the recent NA cold winters were worse in a historical sense, up there, than down here. I should have remembered that because I knew about last year's shocking low temps on Martha's Vineyard. If a 50% arboreum was only 6' after 35 years, yes I would assume it died back in 85 and/or 93/94. So...maybe not quite as hardy as I'd thought it was.
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Sun Jan 29, 2017 3:23 am |
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johnw
Joined: Sun Mar 24, 2013 2:37 pm Posts: 240 Location: Halifax, NS
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Re: Rhododendron rex
Not sure if Toronto got that cold snap last year, we luckily dodged it by a hair.
David - The bvt x arb cross was done in 77 so reckon it didn't go out till the early 80's. Here 1971-1973 winters were very bad, 1977-1983 hideous and then all was well until the unprecedented cold of 1993, mild ever since. Toronto's cold winters may have been a year earlier or later than ours and I suspect the early 80's cold there was hard on that cross. They had some bad winters after their 1994 horror too. One can only imagine how huge it would be here in the east!
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Mon Jan 30, 2017 3:47 pm |
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Arturas
Joined: Sat Jul 09, 2016 9:16 pm Posts: 49 Location: Klaipeda Lithuania 6B zone 55°42 N
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Re: Rhododendron rex
This is weather record for Toronto last year - pretty cold indeed
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Wed Feb 01, 2017 5:27 pm |
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johnw
Joined: Sun Mar 24, 2013 2:37 pm Posts: 240 Location: Halifax, NS
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Re: Rhododendron rex
Arturas - Interesting - Can you find one for the same months of 2011 & 2014?
john
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Wed Feb 01, 2017 6:20 pm |
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Arturas
Joined: Sat Jul 09, 2016 9:16 pm Posts: 49 Location: Klaipeda Lithuania 6B zone 55°42 N
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Re: Rhododendron rex
Here it goes. This is resource. Unfortunately records are available only for airports and large cities
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Wed Feb 01, 2017 7:37 pm |
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Arturas
Joined: Sat Jul 09, 2016 9:16 pm Posts: 49 Location: Klaipeda Lithuania 6B zone 55°42 N
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Re: Rhododendron rex
And this is Halifax airport.
For the Halifax city (white dot on the map below, I guess), which is closer to coast only max temps are available,
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Wed Feb 01, 2017 7:48 pm |
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Arturas
Joined: Sat Jul 09, 2016 9:16 pm Posts: 49 Location: Klaipeda Lithuania 6B zone 55°42 N
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Re: Rhododendron rex
And here go the min temperatures for my city - again closer to NS, but winters in 2010-2013 were colder here
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Wed Feb 01, 2017 7:59 pm |
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johnw
Joined: Sun Mar 24, 2013 2:37 pm Posts: 240 Location: Halifax, NS
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Re: Rhododendron rex
Arturas - I assume the attached was for Toronto. If so you can see the bvt x arb blew buds at approx. -5F/-21c.
In 2014 it was obviously damaged by that -25c.
The Halifax Airport info is useless as that weather station is 40km inland and nobody lives there.
Here in the city I have not gone below 0F since the very early 90's.
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Thu Feb 02, 2017 2:15 pm |
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Arturas
Joined: Sat Jul 09, 2016 9:16 pm Posts: 49 Location: Klaipeda Lithuania 6B zone 55°42 N
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Re: Rhododendron rex
After posting the temperature timeseries images I did notice the significant difference in the pattern of winter temperatures between my city and Toronto (and Halifax). The cold spells in Klaipeda are very brief and sharp ( only a couple of nights every year below -15 C), while in Canada the temperature change during the winter is more gradual. I don't know what is better for plants - sharp and short or long and gradual - what is your opinion?
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Thu Feb 02, 2017 3:03 pm |
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David Matzdorf
Site Admin
Joined: Mon Oct 29, 2007 4:06 pm Posts: 5321 Location: Islington, London UK
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Re: Rhododendron rex
_________________ 51º33'07"N x 0º07'21"W
43m (142 feet) ASL
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Thu Feb 02, 2017 6:01 pm |
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