New Growth on Rhododendrons
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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: New Growth on Rhododendrons
Here's Scott's alpine macabeanum.
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Tue Jun 21, 2016 9:32 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
Tim - apparently the alpine form of macabeanum is hardier, but I did not realize the leaves were that small. Thanks for the picture to give size perspective. Still a nice rhododendron. Had not heard of the Coastal Maine Botanical Garden. Will visit their website.
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Tue Jun 21, 2016 12:28 pm |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: New Growth on Rhododendrons
Anne, hi, Tim tipped me off about this thread. I am a sorta serious collector in northeastern MD.
Congrats on your plants, but a few questions if you don't mind. Are you near mountains in Missouri (Ozarks I guess) and perhaps in a place where nights are a little cooler...mountain valley or something? I see what looks like old forest growth, but I understand that large sections of Missouri would be former farmland and/or plains.
EDIT: I see now you replied elsewhere that, as I expected, you are in the Ozarks. Can you share your exact elevation? What is a typical night temp. there in summer? All of the big leafs seem to grow fine on volcanic soil around Lake Maggiore, where summer nights are about 61F. Hard to believe your nights are that cool, but they are probably cooler than mine and closer to Tim's.
Of all the rhodies you've tried in-ground, have any died of root rot for you? I'm not too surprised you're able to, for example, keep R. rex alive in a pot, because I've found that for the most part, it's not until you plant out rot-sensitive varieties that they become inoculated with phytophthora.
Is it possible your "neck of the woods" was completely unsettled before you moved there, and, as human immunologists might say, "naive" to western horticulture? Meaning, no one before you had ever planted nursery grown plants of any kind in this area? Looking at your 'Nova Zembla' for instance: looks very healthy but I think overall, that would be considered a temperamental plant as far south as Missouri. Unless, again you are in the mountains, or on some kind of specially well draining soil. Whereas my garden, according to elderly neighbors now departed this earth, was owned by horticulturalists in the 1950s & 60s who brought in a lot of outside grown plants. So surely over the years, the now mostly 'cosmopolitan' types of root rot like Phytophthora cinnamomi had a chance to get established around here. These days, compared to olden times, nursery plants are more likely to be free of such pathogens. So for example if your 'Nova Zembla' started life as a Briggs liner, it was essentially 'aseptically' produced, with respect to root rot organisms, until you planted it. (cars and trucks entering that nursery have to drive through a tire-cleaning sanitizer solution, or so I'm told!)
You don't mention using any anti-fungals so I assume you don't, but just wanted confirmation of that.
Thanks! And thanks for posting here, it's good to know someone else is being a rhododendron 'pioneer' outside the PNW!
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Sun Jul 03, 2016 11:49 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
Hi David - thank you for contributing to the thread, and for your interesting questions, which I will attempt to answer to the best of my ability. 1) I do live in the Missouri Ozarks, in the south-central part of the state, about one hour from the Arkansas border. 2) I live on a south-facing ridge, and my elevation is approx. 800 - 900 feet. See accompanying photo #1 showing the view from my backyard. 3) The average summer 2015 night temperature ranged between the upper 60s and low 70s. Summers are humid. 4) Most of the species I have are still in pots, except for chionoides, decorum, several maximum, and a small wasonii. I have moved some up to larger pots, and that will be done this summer for others. 5) The land all around here was previously wooded, and was cut over between 1887 and 1920, primarily for railroad ties. There was no habitation or farming on my property prior to my moving here in October 2006. See accompanying photo #2 showing some of the sparser area of my land. 6) The soil here is best described as rocky and limey. The water is limey and hard. I replace the native soil with a mixture of Miracle-Gro potting mix and finely ground pine bark mulch. I did not originally plan to plant anything in the area below the house, but the urge hit and, of all things, my focus has been rhododendrons. See accompanying photo #3 showing PART of the lower area, viewed from the east. More has been planted since. 7) I do not use any anti-fungal treatments.
Many of my hybrid rhododendrons come from Whitney Gardens and Nursery in Brinnon, Washington, including the 'Nova Zembla' you referred to.
As with any venture, there are failures, and I try again. We frequently have windy conditions, another situation not suited to rhododendrons. Up until June 2014 I watered everything by hand, which not only included the area below the house, but plantings all around the perimeter of house, and a row of 30 white pines extending approx. 200 feet north to south on the west property line, newly planted in October 2010 as 6' - 7' trees. See accompanying photo #4 for a partial view of that planting. Now there is an underground irrigation system for the lower yard (which does an adequate job, but not perfect), and soaker hoses for the white pines and most of the perimeter of the house. Hand watering takes about 1-1/2 to 2 hours for the balance of the plantings. The abundance of native shortleaf pines is both a help and a hindrance. They provide high shade and pine needles, but the roots venture into the planting sites, take up the water, and often intertwine with the roots of the shrubs. Taking into consideration that I do almost everything around here myself, I am personally pleased with what has been accomplished, and would not change what I focus on and enjoy.
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Sun Jul 03, 2016 10:22 pm |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: New Growth on Rhododendrons
Anne, thanks for the followup. At your elevation, nights are indeed warm. Looking around, this is one of the highest elevation towns I could find climate stats for near you: https://en.wikipedia.org/wiki/Springfield,_MissouriElevation 1300 ft., and even there it's a little warmer in summer than . You should just be aware that no R. rex, for example, has been known to survive long term south of NYC. In the heyday of Rarefind in NJ, they certainly tried both liner sized plants and hundreds of seedlings, and none made it through the summers. But believe me, I will not begrudge you if you do get them to grow. It sounds like it could be that you wouldn't have as wide ranging a population of root rot organisms and might be found either here or at Rarefind. But I would certainly recommend that, when you plant some of the high-elevation species out, you at least consider using Actinovate or something similar. I guess you are aware of the 'Southgate' rhododendrons, or the other hybrids involving R. hyperythrum like 'Charles Loomis', 'Martha Player', or 'Opal Thornton'? They are incredibly heat and root rot resistant, 'Charles Loomis' now probably being my biggest rhododendron, and growing fast in almost full sun with no supplemental water. At least you have the high shade though! I am jealous of that, as I'm running out of places to tuck rhododendrons until my (hopefully) super fast growing Chinese Taxodium hybrids are towering over parts of my garden. It does help mitigate the heat.
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Mon Jul 04, 2016 1:05 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
David - here is the temperature history for Eminence, Missouri for June, July & August 2015. Please click on "History" near the top after you open each link to get the daily numbers. I copied and pasted the URL but it did not leave that window open. http://www.usclimatedata.com/climate/em ... 120/2015/6http://www.usclimatedata.com/climate/em ... 120/2015/7http://www.usclimatedata.com/climate/em ... 120/2015/8Summer 2016 is destined to be hotter than last year. Springfield, Missouri is 2-1/2 hours west of where I live. I am not sure of their elevation, but they are the third largest city in Missouri and are in the middle of flat, unforested country. Where I live is away from any development, and is surrounded by forest. I have two 'Charles Loomis' and had the opportunity to buy some hyperythrum hybrids at our Ozark Chapter ARS Fall 2015 meeting. I chose not to. Stan Southerland spoke at that meeting. http://scholar.lib.vt.edu/ejournals/JAR ... -means.htmMy hodgsonii and rex ssp. fictolacteum made it thru last summer. They and rex ssp. rex made it thru last winter in a raised bed planter. I will put my best efforts forward to continue to care for them. Pictures herewith are in the order as listed above. I appreciate your suggestions. Stay tuned, as they say.
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Mon Jul 04, 2016 8:22 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
David - attached is a topographic map of the area where I live. If you wish, you can click on the unmarked copy, then view it at a larger percentage. I calculate my elevation to be approx. 800 - 900 feet.
Last edited by Anne Rhody on Wed Jul 06, 2016 6:44 am, edited 2 times in total.
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Mon Jul 04, 2016 9:24 am |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: New Growth on Rhododendrons
Anne - good looking plants. I look forward to your updates! In the future for any high elevation SW Chinese/Himalayan species, or hybrids significantly derived therefrom (hybrids of R. forrestii and R. wardii are particularly hopeless) I plan to only focus on obtaining grafted plants in the future. It just isn't worth the risk of having a plant last 2-5 years and then potentially drop dead. There are exceptions: most of the Long Island bred R. wardii hybrids (i.e., yellows) seem pretty tough here so far. It's possible that they were early on selected against root rot susceptibility, versus yellows bred in the chilly PNW like the gorgeous 'Nancy Evans'. OTOH even with some of those, I'd feel safer in the long run if they were grafted. 'Capistrano' got to be a big, good looking plant here, never any sign of trouble, and suddenly dropped dead after a huge summer rainstorm that broke a drought. That seems to be the absolute worse thing to happen...hot dry soil getting a bunch of hot water poured on it. Phytophthora goes crazy...maybe they sporulate when it's dry and have a huge flush of growth and root attacking after it rains or something.
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Tue Jul 05, 2016 2:18 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: New Growth on Rhododendrons
Thanks for information Anne. Your big leafers look great. I'm excited to hear them growing in your area since your pushing the limits with summer heat and winter cold. Today is the muggy-ist day of the summer......brutal for us but likely not for you. It's 74F and 68F dew point........brutal.
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Tue Jul 05, 2016 3:56 pm |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
Tim - we are having hot and humid weather here. This morning there was dense fog, then the sun burned it off. I worked out there for 5-1/4 hours and was sweating profusely. I think you are kidding me when you say that 74F there is "brutal." David - you have some good ideas for keeping plants long-term by having grafted specimens. Good luck there. I also have kesangiae, acquired this spring, and will be getting macabeanum this fall.
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Tue Jul 05, 2016 11:59 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: New Growth on Rhododendrons
Anne, the 74F wasn't brutal, but our dew point was 68F. We've been use to dew points below 60F. Tomorrow is suppose to hit 90F for us, grrrrrrr.
I'm glad to hear you received a R. kesangiae, I have a small one too......very nice looking. I hope mine has a second flush this season. Do your big leafers have two flushes per season?
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Wed Jul 06, 2016 1:39 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
Tim - I have never calculated dew point here. Can you tell me how that information is helpful? Thank you. So far, my big leafs have not put on a second flush, but for most of them this is only the second spring that I have owned them. Looking forward to future years and the possibility of a second flush. I buy my species Rhododendrons from RSBG and Chimacum Woods Nursery. Where do you buy your species rhododendrons? Do you visit any Facebook pages for Rhododendron groups? There are several that I participate in, including two Danish pages and a French page. One in particular you may enjoy - https://www.facebook.com/groups/4363777 ... d_to_groupLook for posts by Hans Elberg, as well as some others, to see some really nice rhododendrons, including species. In order to post on some of these group pages, you need to submit your name for approval. Hopefully my sharing the link for this Danish group will not be an issue for them.
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Wed Jul 06, 2016 4:40 am |
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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: New Growth on Rhododendrons
Anne, dew point tells us how humid/muggy the air feels (besides telling us the temperature at which dew will form). I don't calculate, just use the web sites which post it. Here's an example of current data for our areas (I didn't find a weather station for Eminance, but a somewhat close town.
My area has a dew point of 64F and your at 75F. WOW your 75F is incredibly high! Our area generally does not get dew points above 72F, anything above 70F dew point is short lived for our area. Dew points tell us how uncomfortable the air feels (does the air conditioner need to be turned on). When dew points are less than 60F, the air feels comfortable, between 60-70 you'll say the air is muggy and will sweat easy, above 70F is 'brutal' and very uncomfortable. I can't imagine a dew point of 75F......that's very, very muggy air. My blood is not use to so much moisture in the air.
My big leafs have not put on a second flush either, but my seed grown hybrid seedlings are flushing for a second time. The only species putting on a second flush is R. arboreum ssp. cinnamomeum which seems very happy.
Here's a photo of a second flush from ARS 15-388, 'Vulcan' X macabeanum, M. Bones #1, Richard Flavell, CT. Second flush likely since its seed grown and still small.
I buy my species Rhododendrons from RSBG and I start from seed. Many of the species I'm interested in don't thrive in our climate so I'm trying hybrids which have some genes from Rhododendrons which can tolerate our climate. I love the big leafers so most of the seed grown plants are hybrids with big leafers.
Here's a baby plant of Hardy Giant x macabeanum, seed by Norman Beaudry. It's already producing leaves to 10" and the plant is tiny. Look how small the plant is!
Here's another hybrid by Norman Beaudry, it's a Hardy Giant x Laramie. Larimie is a macabeanum hybrid. That's a 6" pot and 18" patio stones for scale.
I don't use Facebook, someday. Thanks for the link. I participate on the Yahoo Rhododendron group. Are you a member? Please join if not.
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Wed Jul 06, 2016 8:01 am |
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Anne Rhody
Joined: Mon May 30, 2016 3:16 am Posts: 195 Location: Missouri USA
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New Growth on Rhododendrons
Tim - thank you for explaining the dew point. Yes, it is very muggy here, particularly in recent days. Thank you very much for taking time to share some photos of your rhododendrons. They are doing well, and you have interesting varieties. I will look into the Yahoo Rhododendron group, as I had not heard about it previously. Happy Growing.
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Wed Jul 06, 2016 2:31 pm |
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davidmdzn7
Joined: Tue Jun 14, 2011 12:01 pm Posts: 412 Location: Maryland, USA
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Re: New Growth on Rhododendrons
Once upon a time, we had, in late August, a "perfect" setup of a somewhat oddly positioned Burmuda High with slow winds moving onshore over the Pamlico Sound and then moving over the waters of the Bay, at their warmest at that time of year. I am at the northern tip of the Bay. Although the temperature was only 83F, the nearest weather station I trust was reporting a dewpoint of 78F. I have never felt such humidity, particularly since at an air temp of 83F, there wasn't so much a sense of heat radiating into you - it was hazy of course and the sun was partly obscured - it was just like you were almost drowning in something invisible or being suffocated. When you stepped out of the house you felt for a moment, "oh it's not so hot", but nonetheless you instantly broke into a sweat. Even during serious heatwaves here when temps were near 100, the dewpoint was "only" around 74F or so. Coastal parts of the Arabian Peninsula sometimes have dewpoints in the mid 80s or higher. I simply cannot imagine how awful that must be for months on end.
It's actually really interesting how for any given dewpoint, the temperature at which you experience that dewpoint gives you a clue as to where you are. Especially if you factor in sky conditions. I remember touring Rice University in late October...thank goodness I didn't get in, I wouldn't have liked it. Superficially it was only a little warmer than it was in Virginia at the time, maybe 80F instead of 75F. The sky was blue and autumnal looking... But when we are having our mid-fall weather, of course, the air is pretty crisp with DPs in the 50s. In Houston even at that time of the year, the dewpoints were high for those temperatures, meaning relative humidity was high, and there was a certain clamminess everywhere that you just wouldn't feel at almost any time of year in the DC area, except maybe after a late spring thunderstorm or autumn tropical storm that dumps a lot of rain.
From a gardener's POV though, in a continental climate, muggy is good - it means there's enough humidity in the air that the possibility at least exists of triggering thundershowers. I remember in the worst drought years, the air felt on the whole drier. Also, firmly believe that for most BLEs including most rhodies, at any given temp they are slower to dry out if the air is humid. The susceptibility of roots to rot is wholly separate issue, physiologically speaking.
Anne I guess you are involved in the local ARS chapter. Is there anyone else in your part of the midwest experimenting with these types of species?
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Wed Jul 06, 2016 9:19 pm |
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