The understock you must use for this 5 needled species is Pinus strobus, Pinus wallichiana or Pinus armandii.
The last one is the best one because it's less sensitive for root rot when cultivated in pot.

The tree is pinus rudis mistaken as pinus montezumae
seen it myself nice tree.

It's probably the reason he is so hardy in winter !

Clement

"The understock you must use for this 5 needled species is Pinus strobus, Pinus wallichiana or Pinus armandii"

No!! It is not a pine in subgenus Strobus - not all 5-needle pines are in that subgenus. It is in subgenus Pinus, section Ponderosae. I'd graft it on Pinus ponderosa, or Pinus coulteri. At a pinch, perhaps on Pinus nigra.

"The tree is pinus rudis mistaken as pinus montezumae "

Pinus rudis is a synonym of Pinus hartwegii, and it isn't that. The Sheffield Park tree (which I have seen, and seen others of the same type in other UK gardens e.g. Bodnant) matches high altitude (~1800-2500m) populations of Pinus montezumae found on the drier western part of the Sierra Madre Oriental in northeastern Mexico. Been there, seen them in the wild (but didn't collect herbarium specimens due to sporulating Cronartium rust disease which I didn't want to bring back, and a poor seed year so no seed).

More typical P. montezumae occurs further east in the Sierra Madre Oriental (where moister) is similar in appearance, but has greener foliage. P. hartwegii occurs in the same area, at higher altitude (2500-3700m).

If considered distinct enough to merit treatment as a separate taxon, it doesn't have a name, but could be described as a new variety or subspecies of P. montezumae. Difficult to define though as it intergrades clinally with normal P. montezumae. Someone would need to go to Mexico to study the full range of variation in wild origin trees before describing anything formally.

Resin

Thank you all and especially Resin,as your information gives us at least some clue concerning the hardiness of the tree in question.
I guess there is no 100% satisfactory solution for splitting off geographical variants,at whatever level, unless a population grows completely isolated and if there are no intermediate populations to be found. I agree,only thorough field study can confirm or otherwise. T.

Resin, thanks for your info.
I never came across this species, can you show us a pic of this one?
Thanks in advance!

The 'Sheffield Park' specimen, is this a cultivar or just a species tree that grows there?

Grafting makes the one grafted a clonal selection. Apparently the cultivar name 'Sheffield Park' is being used to differentiate this selection.

tentatively accepted name in the RHS Horticultural Database

Here is a link that might be useful: RHS Horticultural Database / RHS Gardening

"I never came across this species, can you show us a pic of this one?"

Don't have any pics myself (took a pic in Mexico, but typical for my photographic abilities it came out badly blurred!). Pic of one of the same glaucous-foliage strain at the link below (scroll to end of page).

"The 'Sheffield Park' specimen, is this a cultivar or just a species tree that grows there?"

Both. It is a species tree growing there, that has been selected and named as a new cultivar. But many other old Pinus montezumae specimens around Britain share the same characteristics, and may well be from the same seed lot.

Resin

Here is a link that might be useful: Gigha Gardens

FWIW, there are 2 old 5-needled Mexican pines on the campus of the University of Florida and they appear to be grafted. Most people don't notice them as they superficially look like mature longleaf pines. Apparently, they are P. montezumae. I will try to post pics soon. They are quite attractive. I might try grafting them this winter. They would have survived the epic freezes of the 1980s when single digits F were recorded.

These particular plants have been grafted onto Pinus uncinata, and are all looking ok on that particular understock. 5 needled understocks were originally tried but all failed.

Hi Blue. Does my plant come from Lime Cross Nursery originally? (I checked their catalog, but it isn't in there - so no info). Do you know of anyone growing one since a certain number of years on P.uncinata understock? Thanks! T.
PS. Any particular cultural requirements for P. uncinata.?

Yes, they do come from Lime Cross Nursery, and they are the first ones to be propagated and sold, so can't really say what long time viability will be. saw the main plant at the nursery today! only about 3-4 yrs old I think, but already about 2 1/2 metres high, with really good long thick blue needles...graft union looked perfect also.

Pinus mugo subsp. uncinata is probably not ideal as a rootstock, as it a sairly slender, slow-growing tree, whereas P. montezumae is fast-growing in girth and soon puts on a stout trunk. So there may be problems with stem diameter growth differences at the graft.

Better to try Pinus ponderosa, P. radiata or P. muricata for a rootstock.

Resin

Thanks for the explanations,everyone. I hope the early winter isn't causing too much trouble on the conifer scene... stopped me from getting on with the garden & building operations for a while! There is some let-up at the moment with lots of sunshine, but it's getting bitterly cold again! Brrr.. T.

As Resin says, might be a problem long term , but so far the scions and rootstocks are in perfect harmony and growing away at the same rate.

"as it a sairly slender, slow-growing tree"

That should of course read "as it a fairly slender, slow-growing tree" ;-)

Resin

{{gwi:867578}}

Pinus ? "Sheffield Park"
Clement

Hey Clement! I quickly rushed outside to see if my plant was still there! Yours is obviously a sister-plant of mine as the tag is exactly the same! Were you in at the Courson plantshow last october or did you make a quick dash across the channel to snatch one up at Lime Cross Nursery???
Looks like I come up with SOME useful information from time to time! T.
PS Thanks for sending me your plantlist last september. I didn't order from it as I'm way behind with my work schedule. If at all possible, send me an updated list in march or april. Thanks again

Lime Cross Nursery sent 2 plants to me last spring.
Clement

long time coming, but I don't think any of you have this right about the root stocks for pinus montezumae. Botanically, it's not about matching the needle numbers- and pinus armandii, wallichiana and strobus are definately not suitable matches.

I am the largest supplier of this species in the UK, and hold most of the UK stock of young plants and seedlings (25 to 130cm), plus many more long needle/rare conifers. Want to know more?- contact me at goakey101@gmail.com for a full stock list