prolonged fall color on Chinese Taxodium hybrids

Discussion in 'Gymnosperms (incl. Conifers)' started by davidrt28, Dec 18, 2022.

  1. davidrt28

    davidrt28 New Member

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    These hybrids are certainly not a secret, but they aren't common in US commerce yet
    Taxodium Update by David Creech | American Conifer Society

    As my trees have matured, I notice that, in my climate at least, they have very prolonged fall color. This T406, now known as 'La Nana', has looked like this for over a month. I can only assume in Texas they do take on some color, but much later in winter. I also have a T502, aka 'Banita', which has somewhat inferior branching but is otherwise similar. So far it's been down to 20F/-7C. When it really gets cold next week, they will probably start to lose most of their needles and be bare by mid-winter.

    There are a few regular bald cypress in the area and they have long since completely lost their needles. Metasequoia holds on longer but not nearly this long and it isn't such a vibrant shade.
     

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  2. davidrt28

    davidrt28 New Member

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    The freeze down to 5F/-15C did hasten the fall of the remaining needles, but it still takes time. Especially on the largest hybrid of mine, the T502, pictured below. It would appear that, unlike the marcescence of an oak that decreases with age*, this gets more stable as the tree gets older. It's not looking quite like this anymore, but this was how it looked on the 1st of January, about a week into the thaw. A lot dropped in the past few days as we had a windy spell. Also note that the observation about bad branching doesn't apply to my specimen...because I've been working on it for the past 10 years! Dr. Creech and others have found T502 needs more of that sort of correction, while T406 forms a strong leader on its own. (In the foreground is my Cryptomeria 'Araucarioides'!)

    Anyhow it's beautiful and pretty distinctive effect in the landscape at this time of year. Hopefully these cultivars see more widespread availability.

    * - at least what is happening with my Quercus variabilis, which is good because it's an ugly trait on those! Obviously tardily deciduous <> marcescence <> semi-evergreen, but they are similar. There are attractive semi-evergreen or tardily deciduous angiosperms like my 'Little Ruby' Dogwood.
     

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    Last edited: Jan 16, 2023
  3. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Has anyone done any studies of the potential harm that widespread planting of these clones might have on the genetic composition and fitness of natural populations of the species? Seems to me that their cultivation should be restricted, or even banned, within pollen dispersal range of native stands of Taxodium.
     
  4. davidrt28

    davidrt28 New Member

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    Wow...where to begin. Why is this suddenly a concern? For one thing some treatments consider all Taxodium to be one species, so the hybrids would just all be Taxodium distichum, not even nothospecies! And has the cultivation of any other not strictly native species (but arguably, not 'non-native') in one area actually harmed the "genetic composition and fitness" of a native species? Have pines in the interior northern Piedmont of the US east coast been "polluted" by "non-native" loblolly pines? From roughly Greensboro, NC, though South Boston VA and up to Gainesville and Loudoun county west of DC, there were at times thousands of acres of loblolly plantations. We're talking literally ORDERS OF MAGNITUDE more "trees from another part of the same country" (significant because the obsession with native plants is, in fact, a bizarre form of actual nativism) than will ever be planted of these 'hybrid' cypress. Did they harm the genetics of the native Virginia or table mountain or whatever pines? Even if you take something wildly invasive like Celastrus orbiculatus, it supposedly produces mainly infertile hybrids with the American Celastrus scandens. And so what if they weren't - Celastrus scandens was already a thuggish species that strangles saplings. The genes from the oriental species would just make it better at doing that! Even if I discount weeds, your concern might be less misplaced with examples they are fully non-native: Look at Exbury azaleas mostly derived from Asian R. mollis, that have been cultivated for at least 100 years on the US east coast, often near US native species. Are they thought to be damaging them with hybridization? I guess someone, somewhere, who worries about how many angels can dance on the head of an ecological pin, is actually worried about that. Has it ever been brought up in a gardening forum about Ericaceous plants in the 20+ years I've been reading them?
    Your odd comment actually opens a whole gigantic can of worms about what I'm fond of calling the 'silly cargo cult of native plant supremacy' that I've [gladly] discussed elsewhere, but don't have time to go into RN. Anyhow you can rest assured I am many, many miles from any native stands of cypress. (which, who knows, might have undergone assisted migration from Native Americans at one point? Oh nos! Maybe a very thorough study of the fossil record should undertaken to ensure they actually 'belong' as far north as Delaware! Mother nature forbid they end up occupying an ecological niche they are imminently suited for due to the intervention of one lifeform [humans] rather than another [birds]!)
     
    Last edited: Jan 17, 2023
  5. davidrt28

    davidrt28 New Member

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    Cryptic Biological Invasions: a General Model of Hybridization | Scientific Reports

    New opportunities brought by hybridization
    Determining whether hybridization cases are natural or human-induced is a high priority in conservation biology3. In this last case, the loss of important local adaptations due to genetic swamping, the behavioural change influencing ecological interactions, and the reduced likelihood of population recovery due to reduced reproductive value, may certainly represent a serious threat for native species14. However, even when hybridization is induced by humans, it is not necessarily a threat for native biodiversity. Indeed, hybridization is a source of genetic diversity that may be important for adaptation to changing environmental conditions, particularly to prevent the negative effects of habitats that are modified by humans. For instance, the novel genetic architecture visible in our phenotypic landscapes may also represent the increase of genetic diversity brought by hybridization. We exposed different situations in which theoretical parental taxa admix and generate new hybrid individuals that may be found at high frequencies. If those hybrids do not have a much-reduced fitness and do not undergo a change in ecological functions as compared to their parental organisms, hybridization may simply represent an increase of genetic diversity.
     
  6. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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  7. davidrt28

    davidrt28 New Member

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    So my question is why this suddenly applies to this genus and not the literal 1000s of other where gene flow could, in theory, take place between cultivated and native stands of plants. In the 15 (?) years I've been cognizant of your online presence I don't recall you issuing a warning about something like this no matter what conifer or tree species people were talking about. Is there a reason you think Taxodium is especially susceptible to genetic swamping?

    Again, let's compare a plant 100s of times more popular than the Chinese bald cypress hybrids will ever be. (except in China, presumably!) The long ago and naturally occurring cross between Q. robur and Q. alba has surely resulted in some gene flow from European to North American white oak populations, but nobody worried about it, or warns that commercial cultivars of it not be planted near stands of White Oak!
     
  8. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Fair point that I've not raised this question before with other plants, because it is equally valid with them too. So why have I just mentioned it with Taxodium? I guess, because it's a genus which (along with other conifer genera) I'm particularly interested in. But also because there seem to be particularly strong commercial interests pushing these new cultivars in a way that I haven't seen with other cultivars so much (again, probably because of my particular interests, not because it isn't happening); so my fear is that within a few years, they will be 98% of all Taxodium being planted, rather than the tiny fraction you seem to be suggesting.
     
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  9. davidrt28

    davidrt28 New Member

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    Well I wouldn't worry about it. I keep my finger on the pulse of what the US wholesale nursery-industrial complex is offering, and in spite of Dr. Creech trying to popularize them for over 10 years, I've never seen these hybrids in those sales channels. Places like this Colesville Nursery
    In fact it took an astonishing long time for them to even show up in the 'collector's rarities' mail order nursery listings.
    It finally did here:
    LaNana Kneeless Cypress Tree - Trees - Almost Eden

    19 available. Going to take a long time to be "98% of all Taxodium planted" at that rate! I can guarantee you that at least 100X as many 'Peve Minaret' have been planted in the US SE and east coast as have been planted of Creech's hybrids. So you should sooner lose sleep over those causing native cypress stands to shrink! Yes, 100X as many. At the ultra trendy Styer's nursery in SE PA, I once saw what looked like half a truckload of Peve Minarets for sale, must have been well over 20. And that was over a decade ago. Colesville has sold them for years too.
     
  10. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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