Any Quercus insignis in Britain Im going to try one.
Jim where abouts are you in Devon we could exchange
trees.

Woo. That's a big acorn. I can't imagine what the tap root is like! perhaps a gallon pot with bottomless sitting on chicken wire to air prune a beast tap root???

HavenÂt heard anything to the contrary, but neither has anyone heard anything supporting the zone 7 designation. I know of very few Evergreen oaks grown up to zone 7. Deciduous, yes, past, but evergreen? Im very dubious. Many evergreen oaks from the costal plain wont grow reliably in zone 7.

From what I have read that while it may be from a mountain area, its habitat the moist jungle of the low areas. The mountains of mexico have great, great habitat variance. Go down enough and boom you can end up in jungle. Just the area, "mountains" is misleading, because this is a species of the jungle. Guy stenrberg stated himself in his book on native trees of north America that he came across this species in the moist jungle.

I may be misremembering, but if memory serves correctly, the taproot on Q.insignis emerges from the end enclosed inside the cap, as opposed to the exposed 'tip' end, as is typical of the oaks most of us are familiar with.

Q. insignis does indeed grow up in the mountains. I've seen photos of it growing with a nice blanket of snow covering it and it's surroundings(in an area that I would say is border line zone 8/9 based on the owner's experiences with the winters there). Hardly what I would call the moist jungle. I'm not disputing Guy's experience, just saying it also grows up in the less than tropical mountains. Most all of the American tropical Oaks don't grow down in the jungle, but in the higher altitudes of the mountains(probably about 99% of them if I had to put a figure on it). There are a few which do grow down to the jungle area though.

Also, I didn't claim zone 7 hardiness(I claimed zone 8 as my best guess), but it wouldn't surprise me if someone collected acorns from one in the higher altitude most Northern parts of it's range and successfully grew it in Southern zone 7(but that's a maybe, just like I originally said). Since nobody has ever tested the hardiness of this species that I know of, this is all just speculation. That was my point about the places that grow it also, it's because they are the only places I know of that have tried to grow it, not because they're the only places it was successfully grown, so the fact that they are zone 10 gardens doesn't necessarily say anything about their winter hardiness. Those gardens all grow Quercus robur too! If someone collected acorns from trees growing in the most low level tropical location for the species, they could very well turn out to be zone 10 trees. Who knows for sure.

fledgeling said, "Im very dubious"
No problem with that, let's hope some people start to test it out by trying to grow this species in more areas. Now that would be exciting. But for some reason few gardens show much interest in Oaks. I guess because they don't have showy flowers to attract the tourists. (a little sarcasm!)

Lastly, I grow several different evergreen Mexican Oaks here in zone 6 Kansas, as well as some evergreen Oaks from other parts of the world. Some that are native to areas that would classified as zone 9 or 10 even. Most have done surprisingly well, while a few of the more tropical ones are more or less die-back shrubs. Even with that, most would of never guessed they could ever make it through 1 winter up here in any manner. So, again I'd say from my experience(and others I've talked with) that many Mexican Oaks turn out to be much more winter hardy than you would expect from their native range.

And Lucky, you are correct. This seems to be an unusual characteristic which is somewhat common with Central American Oaks, but can also be found in a few Mexican and SW US Oaks as well.

"the taproot on Q.insignis emerges from the end enclosed inside the cap, as opposed to the exposed 'tip' end, as is typical of the oaks most of us are familiar with"

"This seems to be an unusual characteristic which is somewhat common with Central American Oaks, but can also be found in a few Mexican and SW US Oaks as well"

Also Quercus aucheri from southwest Turkey

Resin

kman04, which Mexican oak species are you growing and which have had the most success? I've always been interested in this group of trees but never thought any of them would stand a chance here. I have zone 5/6 conditions with several sheltered areas that are just begging for some zone-stretching experiments. Most of our winters here are essentially zone 6 (last year was closer to zone 7) but we are prone to occasional short-lived lows around -20F. I'd be pretty interested to hear which of these exotic oaks I might have a chance with, even if its a small chance!

PS- this is a relatively high precip area so the desert/scrubland oaks are probably out of the question unfortunately.

With an acorn that size, the seedling must be HUGE!

my recollection is that guy wrote that he encountered q. muhlengergii in the "cloud forests" of mexico which are high elevation relatively cool, humid "temperate" forests situated well above the tropical forests. associated with the oaks are other familiar temperate type tree species like magnolias, dogwoods, yews, maples, pines, holly, baldcypress, firs, alders, hickories, and walnuts plus various plants of more neotropical alliances. i cultivate a number of mexican oak species (though not insignis) on the oregon coast which is almost always cool and humid and we certainly can get frosts and (rarely) snow and have never suffured any cold damage on the plants (hopefully i havent jinxed myself by saying that)and some have fuited with viable seed. mexican oaks have been culitvated successfully in north carolina and the NCSU arboretum and my guess is that if you live in a place that can grow live oaks (q. virginiana) with no winter damage you have a good shot at growing some of the mexican oaks.

George,

Do you mean Q. muehlenbergii?

Large-leaved broad-leaf evergreens that can come through serious cold in good condition are quite exceptional. Even among rhododendrons the big-leaf species that aren't tender are comparatively few, the big leaves being an adaptation to dull and damp conditions (even these particular plants have the added advantage of being able to tightly roll their leaves up to look like cigars during cold and dry winter conditions, unlike evergreen oaks).

quercus macrocarpa---yes, my typing gets haphazzard when i get in a hurry.
bboy---i believe that both yuccado and ncsu arboretum indicated that several of the mexican evergreen oaks survived (probably limited) exposure to 4f. q. rhysophylla a fairly large leaved mexican oak has grown very well in salem, oregon (usda 8a) and even self-seeded. that said, as a practical matter if somebody has difficulty growing other broad leaf evergreens under normal garden conditions due to regular low winter temps in their area they are definitely not going to have much luck growing mexican oaks and i would agree that the bigger the leaf the more risk of cold damage.

Yes: duration of cold important. If it only lasts a short time and then warms up again right away the plant doesn't have to endure frozen soil, like it would in the north. That's why a plant living through 14F in California doesn't demonstrate it will live through the same temperatures up here.

For information about other individual specimens of evergreen oaks growing in cultivation in USDA 8 see Jacobson, TREES OF SEATTLE - SECOND EDITION.

Somehow, I get the feeling this species wouldn't make it here in Chicagoland.

pteroceltis,

Some of the better performing Mexican Oaks for me are Quercus canbyi, Q. hypoleucoides, Q. emoryi, Q. fusiformis, Q. polymorpha, Q. rhysophylla, and Q. vaseyana. Out of these, I'd say Q. canbyi, Q. hypoleucoides, Q. fusiformis, and Q. emoryi might grow in a borderline zone 5/6 area with Q. canbyi and Q. fusiformis being the most adaptable to different soils while the other 2 require a very good draining soil. It also helps to grow the trees as large as you can in pots before planting out.

quercus_macrocarpa, Maybe not, but if someone out there crosses Q. insignis with Q. macrocarpa, you might get something similar but much more hardy! Q. tarahumara has acorns of about the same size as Q. insignis but is probably hardier and if someone crossed that with Q. macrocarpa they might get an even hardier giant fruiting Oak! Ok, the challenge is out there, so who's gonna do it now? he he :-)

PS. I know some of the species I listed grow on both sides of the border in both Mexico and the USA.

Agree with bboy's comments. Worth adding that Q. rhysophylla is from northeastern Mexico, which gets a lot colder than southern/central Mexico.

There's a published record (December 1983) of -15°C for Galeana (1700m alt.) in Nuevo León; with the normal adiabatic lapse rate, that would give around -30° at treeline on Cerro Potosi (3700m) unless there was a marked temperature inversion.

By contrast, south of the Tropic of Cancer, even where there is regular snow, it does not get more than a very few degrees below freezing, and it does not stay cold for long, as daylight length is not markedly shorter in winter in the tropics.

I'm going to stick with my estimate of zone 9b or 10 for Q. insignis.

Resin

"if someone out there crosses Q. insignis with Q. macrocarpa"

Which section of the genus is Q. insignis in? Is it a white oak or a red oak (or something different again)?

Resin

Q. insignis and Q. tarahumara are both White Oaks.

"...Q. rhysophylla is from northeastern Mexico..."

I'm not growing these Oaks in zone 8, or even zone 7, but zone 6 and based on their native range I'd say many would guess several of these trees would be zone 8b or maybe even zone 9 trees. Heck, I'm even growing Q. germana (Which it's native range overlaps or comes very close to that of Q. insignis), but it doesn't grow so well for me, and again I'd bet many would think it's only a zone 9 tree. But who knows for sure, you could be correct about the hardiness of Q. insignis.

Why this A or B nonsense your either in Z9 or 10 Resin I
think your over pessimistic when you mention the hardiness
of many trees.

Hi Kman,

How long have you been growing them? Long enough for them to have been around in the last severe winter? I note that Kansas has a record of -40°C, which is not going to do them any good.

Hi Torreya,

Not pessimistic, just realistic. Wait until you've seen a severe winter with -15°C. It's been recorded down your way in the past, and it'll happen again, even despite a bit of global warming (which has after all only lifted temperatures by slightly less than one degree so far).

Resin

Resin

You have a thing about severe winters I would never
get -15c here now that is bl**dy pessimistic.Ilive
near an estuary anyway the SW has the best climate
in Britain for tree growing.

Kman

Hope your oaks thrive despite what Resin thinks.

When I visited a famous nursery in Cornwall one March in the mid-90s a good-sized, long-established Campbell magnolia there had recently been denuded by a hard frost. (Another substantial specimen in the Seattle arboretum, with the same appearance after a fall cold snap died from it). Just about anywhere in the temperate zone can turn nasty from time-to-time, and when that will be is unpredictable. During 1990 we had a hard winter here (PNW USA) that wiped out trees and shrubs that had been here for decades. Other killers were 1972 and 1955, that last one accounting for numbers of "died in winter of 1955/56" notations in files of Seattle arboretum.

Hi Torreya,

Try going to the library, or local met. office, and ask for info in the 1916/1917 winter. Haven't been able to find the minimum temperature for that winter, but the south coast of Cornwall remained below freezing for 3 weeks uninterrupted.

Resin

Many species have indeed shown hardiness beyond what would be expected for their natural range, but any trial shorter than about 50 years and does not include anything less than a unusually cold winter occurring are not reliable indicators of long term hardiness and adaptability.

Absolutely. And we're talking about trees here, so long-term results are highly relevant.

Yep. Cold weather will come. Global warming is all BS. Didn't we have something like Cooling Global back in 1980s? There will always be cyclical of hot and cold climate. To be blaming global warming on CO2 is ridiculously stupid. Solar activities play a much bigger role. Maybe the earth is not tilting like it was before. Who the heck knows but it sure isn't on increased CO2 in the air for sure.

Any way we can avoid a global warming debate in this thread?

Yes: don't post a rebuttal.

Yep.

Wow it takes all my willpower not to point out so many reasons that lou is wrong. Instead, I'll congratulate kman on his success with those Mexican Oaks. I'll definitely be looking into several of them along with some southeastern species I saw growing at the Morris in Philly (i.e. Q. shumardii) and have been impressed with in person.

I'm also quite envious of all you English Folks, you can grow so much! I actually saw some sort of urban forestry census that was done on the Syracuse area and there was a Magnolia campbellii listed- I couldn't help but just break out laughing. I guess that's my sign that I'm a plant geek. A zone5 hardy Campbell Magnolia- now that would be worth something!

If one crossed with Q. macrocarpa, then from which end of the acorn would the plumule emerge?

If someone would like to fund a 20-year research project to find out, I'll gladly give it a go!

Resin

There is no better time to start testing these plants than the present!

The Missouri Botanical Garden has a specimen list with coordinates for 49 individual specimens collected. Nearly all occur at elevations above 700 m., some as high as 2000 m. or more. The distribution of specimens, if we assume this is in any way representative of actual distributions, would seem to indicate that this is primarily a Central American species, with just a bit of overlap into S. MexicoÂs Chiapas region.
Given the fairly wide & sporadic distribution throughout the mountains of C. America, its probably safe to assume some degree of difference with respect to climate adaptation among different populations.
The MBG database, though not especially user-friendly, allows you to examine the distribution of specimens using Google Earth (pretty amazing).

Here is a link that might be useful: MBG Search

Resin

I will look into that and try to find some quercus insignis
down here is it evergreen?

"Missouri Botanical Garden has a specimen list with coordinates for 49 individual specimens collected"

They've only mapped the "Mesoamerican Specimens"; presumably for Flora Neotropica, which covers southernmost Mexico, but not central and northern Mexico. Their main page for the species notes the type locality as Volcan Orizaba in Veracruz.

Resin

Noted. Thank you.

pineresin,

I've been growing most of these Oaks for between 10 and 15 years here. If they all get wiped out in some spectacular cold snap in 50 years, I might not be around to care. Although I highly doubt that at least 3 or 4 of them are much less cold hardy than most of the native Oaks in my area, based on how they've dealt with extremely diverse conditions lately which have damaged native Oaks and left these unscathed.

Also, that -40°C (also -40°F) is somewhat dubious. Nowhere else in the state experienced anything within 5°C(9°F) of that temperature on the recorded date as far as I know and nowhere in the state has experienced anything colder than -31°C(-25°F) in the 102 years since that dubious -40°C was recorded. Plus the record low in my area is only -28.9°C(-20°F).

Also, not to start an argument or anything, but I just read the synopsis of an interesting study suggesting that much, if not all, of the warming average temperatures recorded in the USA over the past 50 years has been due to development surrounding previously more rural and suburban recording stations(ie. big parking lots being built next to stations, or lots of buildings built near stations radiating heat, etc.) Whether the study is correct or not, it's an interesting hypothesis none-the-less.

kman04, take a look at the below site & the work he's doing documenting "official" temp stations:

Here is a link that might be useful: Wattsupwiththat

Thanks very much for all the responses and the picture of the acorn (amazing). I did attempt to post a picture to the gallery but the file was too large.

It has reddish new growth and attractively serrated leaves, quite a 'tropical' look in my opinion. I understand that 'insignis' translates into 'remarkable' or 'noteworthy' - this plant certainly looks it.

Somehow I now have to find a source for getting this oak!

Jim

Right - picture now added to the gallery!

Jim

Might be worth asking Savil gardens for cuttings
also have you joined the British conifer society?

Kman,

How do the oaks look now after last winter? I'm curious how they handled the record cold last year?

This is a years-late response, but Quercus macrocarpa from Texas have acorns reaching over 2”. These are good trees, that, after 100 years or so will be over 100’ tall, with branches that spread far and wide over the other canopy trees. It’s too bad that humans don’t live long enough to see the ultimate result, but these are trees that will leave a similar legacy. Acorns can be collected in late September/early October. They do not remain viable for long, so take some 5-gallon pots filled with soil or mulch and sow your acorns immediately, then plant them as soon as you get home. Future generations will thank you.

1. "give me the food and let me grow. let the rootsman take' CONTROL. who's got seeds for this. it should be spread far and near. don't the permaculture food forest makers of hawaii have this one yet? somebody call their Mexican friends immediately, please. thank you

Me gustan los grandes retos y quiero intentarlo en uno de los climas más severos y fríos de España: el arboreto de Lugán (LUGAN ARBORETUM).