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davidrt28

warm temperate and subtropical plants in various climates

davidrt28 (zone 7)
11 years ago

I'm breaking this off from the other thread, because one thread can only hold so much inanity.

I can't believe I'm going to have to waste time on this logic exercise, but here goes.We need to classify plants by absolute ranges of hardiness.Let's just say 0F, 20F and 32F to keep things simple.Of the set of all plants hardy in each group, some of them will come from cool summer climates and some of them will come from warm summer climates.So this has nothing to do with "I don't know, diversity tends to go up as the climate gets hotter." Of course, generally speaking, there are more species in the tropics versus the tundra. That's not horticulturally relevant when I said I was only talking about "temperate and subtropical plants."

Of any set of plants above, more of the warm summer ones can grow slowly in a cool summer area than the cool summer ones can tolerate a far warmer climate. This is a simple fact that would be recognized by any enzymologist. All enzymes denature at some high temperature set point; obviously they all stop functioning in a conventional sense at 32F, but they don't denature.

There are literally a handful of temperate and subtropical (again, assuming the basic winter hardiness requirement is met) that will not grow in Cornwall England because it's too chilly for the plant to survive. (never mind blooming) There are hundreds of varieties of plants - thousands if you count rhododendron hybrids - that will DIE in the US SE because summers are too hot. When something like a Hedychium isn't grown in the UK, it's because it's too chilly for it to bloom, not because it will die in an absolute sense. People have nursed crape myrtles along in the UK.Again, they just don't bloom or grow well. They don't die.But there are no Cautleyas (ginger relative) in Orlando because they come from high elevations and will die in Florida.
Thus my statement:
As I've said before, far fewer temperate or subtropical plants need a warm summer as need a cool summer.

Is perfectly logical from the simple standpoint of survival. Which, after all, is square one in growing a plant. A cool summer isn't going to magically bring back the Eucryphia I tried to grow from the dead. (or the several Monkey Puzzles I've tried - there, the thread is about conifers!!! LOL) A freakishly hot summer in the UK COULD make a crape myrtle bloom there.

I could spend the rest of the evening citing examples. Please, don't make me. Many Brugsmansias will grow in the Bay Area, slowly perhaps but they will bloom.'Charles Grimaldi' will grow in central Florida or the Bay Area, but B. sanguinea dies in Florida.Again, the plant enzymes can tolerate a cooler summer than in their native ranges, but cool summer plants cannot survive going over their temperature limit. Even a 50% Cornus nuttallii ('Eddies') dies miserably in the east - believe me I know from experience. Yet there's a picture of a forlorn Cornus florida soldiering on in Norway. Not happy, but not dead.Rhododendron hyperythrum, the Taiwanese savior of Southeastern rhododendron enthusiasts, will grow in Scotland.Conversely, hundreds of high elevation Chinese rhododendron species have no hope south of the Mason-Dixon on the East Coast. (or recently, south of coastal Maine!)

This post was edited by davidrt28 on Wed, Nov 28, 12 at 22:46

Comments (25)

  • floramakros
    11 years ago
    last modified: 9 years ago

    Are you planning at any time to post evidence backing up any of the statements you make above?

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Yep, being a political pundit again. You have evidence staring you in the face, yet you say there's no evidence.

    It's not the sort of question academia would waste their valuable time on, but if I looked I'm sure I could find a research paper backing up what I've said. But I don't see reason to do so; it's sufficiently obvious to anybody who has vast experience in the cultivation of ornamental plants. You haven't actually refuted anything, other than saying there's no elephant in the room after the elephant has crushed every bone in your body.

  • salicaceae
    11 years ago
    last modified: 9 years ago

    I would say that one must consider many variables, not just the climate of the native home range of a species. Soils matter alot too. Some plants suffer in the southeast because of the heavy clay soils prevalent in the region (and die from Phytophthora root rot in summer), but will make it here in Florida, because we have sand. But, their failure elsewhere is wrongly attributed to the climate. Also, some Himalayan species do surprisingly well here - eg. Cupressus torulosa, but as a rule, stuff from low-mid elevation in Taiwan is a much better bet.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Well, if there are a bunch of Rothschild rhododendron hybrids growing in Florida...please let me know about it. I'd love to drove down and see them when they are blooming. Florida's sandy soil might allow a small subset of the plants I'm talking about grow there, but by no means the majority of them.

    This post was edited by davidrt28 on Wed, Nov 28, 12 at 23:55

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    And, although I think it's great that you do it, technically your exercises in grafting are "cheating" and only underscore the point I'm making. Often the roots ARE the problem, but I didn't distinguish that in my original post. If a plant can't grow on its own roots, it can't grow. A grafted plant is a kind of chimera.

    This post was edited by davidrt28 on Wed, Nov 28, 12 at 23:56

  • floramakros
    11 years ago
    last modified: 9 years ago

    "You haven't actually refuted anything, other than saying there's no elephant in the room after the elephant has crushed every bone in your body."

    Seriously, how old are you david?

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    This is relevant because...? Have you ever watched the House of Commons on TV?

    I'll only respond further to this thread if there are substantive responses to what I've written. In other words, if I don't respond, you haven't actually said anything substantive.

  • floramakros
    11 years ago
    last modified: 9 years ago

    "I'll only respond further to this thread if there are substantive responses to what I've written. In other words, if I don't respond, you haven't actually said anything substantive"

    Once again he pontificates a load of nonsense and then declares the discussion closed. Not a single bit of evidence to support anything in his essay above, "Please, don't make me" he says. Davey, were you the only kid in your neighborhood with a basketball so they always had to pick you for a team? What in your background encouraged this absolutist behavior?

  • pineresin
    11 years ago
    last modified: 9 years ago

    "We need to classify plants by absolute ranges of hardiness.Let's just say 0F, 20F and 32F to keep things simple"

    If you want to keep things simple, it HAS to be °C ;-)

    Resin

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Ok Resin. I will respond, because it is perfectly substantive to say our system is archaic. It is. But it's the system we use, and most of us are on this side of the pond.
    Now the the ad hominem have died down, hopefully, I'll say I'm "holding a trump card" on this topic. But I'm going to wait a while to show it. I honestly thought someone else would chime in...but maybe that old adage about wrestling with a pig applies! I'll admit: I do like it. But I'm not a pig, and I don't hate anybody; I'm a relentless warrior for the truth.

  • Huggorm
    11 years ago
    last modified: 9 years ago

    "Yet there's a picture of a forlorn Cornus florida soldiering on in Norway. Not happy, but not dead."

    It should be happy if planted in a good spot in the southern parts of Norway, it isn't that cold there. But I do agree with your statements, there is big differences between plants from climates with warm summers vs. cold summers. I have cold summers here, and the USDA zone system does not aply well to my climate. Some zone 4 trees will have problem, but some other zone 6 trees might thrive.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Yes it isn't "that cold" - I presume you mean in winter. But summers are MUCH MUCH cooler than its native range. In fact when I studied the climate of the area it was unbelievable to me that it got enough GDDs (growing degree days, a measure of overall warmth) to harden its foliage for even a zn 7 winter. You realize by early MAY here, our climate is warmer than your climate gets all summer long? I'm not bragging, obviously, given the whole point of my thread. But I'm just pointing out how different our climate is. We're at the latitude of Lisbon and this is about the midpoint of the native range of C. florida...actually somewhat closer to the northern end.

    But...my trump card will explain all. Just wait.

  • Huggorm
    11 years ago
    last modified: 9 years ago

    What about light hours, we have plenty of them in the growing season here up north. It should help somewhat.

    By the way I was in Norway working in may this year, and it was 30c/86f. That should be an all right temperature in may even in eastern US? But it was a little warmer than normal, that is true.

    This post was edited by Huggorm on Thu, Nov 29, 12 at 17:33

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    You would think the long days would mean [summer] light hours are much higher there, but they aren't. Besides light hours don't account for actual solar irradiance. How strong the sun is for each of those hours. Obviously ours is higher over the course of the year because we are closer to the equator.
    Compare Baltimore to Oslo:
    http://en.wikipedia.org/wiki/Oslo
    http://en.wikipedia.org/wiki/Baltimore

    You see that Baltimore has slightly more sunshine hours in May than Oslo does in July! And is warmer.

    This post was edited by davidrt28 on Thu, Nov 29, 12 at 17:46

  • Huggorm
    11 years ago
    last modified: 9 years ago

    But Oslo is much cloudier than Baltimore, and plants will grow even when it's cloudy so you can't really compare like that.

    Of cause eastern US has a better climate for growing trees, there's no doubt about that. Long, warm summers and enough rain most years. Just too many possible species for the gardener to choose from ;)

    This post was edited by Huggorm on Thu, Nov 29, 12 at 18:23

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Right but you mentioned light hours, I gave you light hours. Of course the whole point of the thread (it's alright, easy misunderstanding) is that NW Europe is not necessarily a poorer climate for growing trees. (I'm generalizing; Oslo isn't the best example when talking about an area from there down to La Coruna) There are many species that can at least grow slowly in your climate; and a handful of ones (crape myrtle) that simply can't grow; conversely there are many, many species that would be winter hardy in say, Norfolk, VA, but cannot grow because the summers are way too hot. (all the aforementioned, as well as: Eucryphia, Desfontainia, Ribes, Chusquea, many non-native Aesculus, etc.)

    Our climate is obviously better for growing our natives and some mid-lat., low/mid elevation Asian plants, in the sense they might grow a bit faster or bloom a bit better. But it isn't as though most of those don't grow in maritime Europe.

    I wonder where the Oslo Cornus florida was collected. I wonder if the once notorious difficulty in cultivation in the UK might be resolved or have been resolved by collecting it from its northernmost, highest elevation haunts instead of a place like tidewater Virginia, where it seems plausible the first collections would have been made. The highest elevation towns in upstate NY are not much warmer than the UK in the summer.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    They seem to do alright in the UK now:
    http://www.junker.co.uk/cornus24.htm
    But IIRC I once read the flowering of the first one was a big deal because it took so long.

    Here is a link that might be useful: http://www.junker.co.uk/cornus24.htm

  • pineresin
    11 years ago
    last modified: 9 years ago

    "I wonder if the once notorious difficulty in cultivation in the UK might be resolved or have been resolved by collecting it from its northernmost, highest elevation haunts instead of a place like tidewater Virginia"

    Probably be better to collect at the highest altitude southern populations. Northern ones used to a reliable long winter will have a strong tendency to leaf out too early in spring when given a mild UK winter, and then get caught by late frosts.

    Southern populations by contrast come from a climate where the difference between summer and winter is less marked and the plants are adapted to occasional warm winter weather combined with cooler high altitude summers.

    Resin

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Resin you are correct. Although I think either collection (northernmost or highest altitude southern mountains) would be better able to mature their wood in the UK than say, one from Charleston, SC. I suppose you think of your winters as having warm spells, but record highs in February even as far north as Syracuse, NY, are still higher those in much of the UK, even though the average February high is lower than the average low in any major UK city! Recently, it's quite typical for warm spells to bring temps around 14C all the way up there, even in the dead of winter. And the dogwoods don't prematurely activate. In other words no amt. of continentality you can muster in the UK should phase it. OTOH, Chinese plants are absolutely used to even more consistency than your climate.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    OK. the trump card the proves, beyond a shadow of a doubt, why FAR more warm summer plants can tolerate cool summers, than cool summer plants can tolerate warm summers...is glacial refugia.
    Let's compare the East Coast to the Pacific Coast. In the last Ice Age, the glaciers came about as far south as central Pennsylvania. The currently warm summer areas in the mid-Atlantic and upper South would obviously have had much, much cooler summers, in addition to colder winters. On the Pacific coast, they only went as far south as roughly the WA/OR border. The climate of a place like San Francisco no doubt got a bit colder, but not much. At worst, it might have gotten as cool as Seattle. But guess what...both places have cool summers now. It didn't make a difference if San Francisco had slightly cooler summers, they already are cool - the plants did not require any adaptation! OTOH, the plants of the Southeast had to adapt to much cooler summers. Hence the reason most Southeastern shrubs will grow just fine in the UK, assuming the winters aren't too cold, but very few shrubs from the world's maritime climates can grow in the Southeastern USA. There's no reason to think there would be ancestral/inactive genes in those plants to tolerate warm summers, because they never had to tolerate them. OTOH, warm summer climate plants have had to tolerate cooler summers during glacial periods.

    This post was edited by davidrt28 on Fri, Nov 30, 12 at 19:55

  • floramakros
    11 years ago
    last modified: 9 years ago

    Just out of curiousity david (this is not an attack so don't go off the deep end) why do you edit half of your posts? Nobody here comes close, do you consider most of the stuff you post here first drafts?

  • floramakros
    11 years ago
    last modified: 9 years ago

    ps The reason I ask is half the people here (maybe even more, I don't know what the percentages are, perhaps someone running the site does) only read these messages via email. They only receive your original unaltered posts never the edited ones. I really don't see the point but maybe you have one, I'd love to hear it if you do.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Well, thanks for drawing my attention to this aspect of the site. I didn't know people actually bothered to read it by email. That must be incredibly tedious. Where did you get the 50% figure?
    "why do you edit half of your posts? "
    "I really don't see the point but maybe you have one, I'd love to hear it if you do."

    I tend to write posts while watching television or doing something else so I don't always edit them very carefully. (on CBS, the professor is going to be the drug dealer, if anybody's watching) When the "edit a post" feature came out I thought "hurray, I can proofread even less carefully now that I can edit them later." So, that's why I have to fix spelling or typing mistakes quite often. Most internet Bulletin Boards have had editing for years. Usually fixing mistakes is considered the "point" of editing: I think that answers your last question?

  • floramakros
    11 years ago
    last modified: 9 years ago

    "hurray, I can proofread even less carefully now that I can edit them later."

    But since the vast majority is either reading your messages via email (making editing irrelevant) or reading them contemporaneously only once, what fraction of people are going to read a thread whose last message was several months ago for example? Unless someone's doing a search your messages will never be read again, and I doubt such a searcher is going to care about your spelling mistakes, do people here often criticize you for your spelling? I doubt it. It still seems a pointless waste of time to me, unless you make a huge factual mistake I don't understand why someone would bother but that's just me.

  • davidrt28 (zone 7)
    Original Author
    11 years ago
    last modified: 9 years ago

    Maybe that's the way you read the board. Although I've been here a lot recently, sometimes I don't visit for a week or so and have to catch up on many threads of interest to me. And some people obviously visit only once a day. I finish my edits in the first few minutes. They will not see the old versions.
    It would shock me if many people read by email but I really don't care. I don't mind if they see the unedited version. I can't imagine what a nuisance that would be, even reputable merchants like amazon already send me more emails than I want to receive. Email overload is a widely accepted fact of internet life so why would people want to receive more than they have to? The whole point of WWW messageboards like this in the late 1990s was to replace mailing lists. My brother is a college professor and says he gets 200-300 emails a day.

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