Pinus Pinea UPPER Hardiness Range?

[ShadyStump]

I've been thinking about Italian stone pine for a while, but I keep finding conflicting information on their temperature and dormancy needs in winter. I know it won't likely do well in my zone 6b outside for winter, so I'm wondering what the requirements are on the other end of the spectrum.

I see them listed as zones 8 to 11 one place, but then 7 to 9 somewhere else.
Mostly I'm wondering about the minimum dormancy requirements, chill hours, whatever. That should give me an idea if it's something I can manage now, or if I'll be saving homegrown pine nuts until I have the wherewithal to build a greenhouse or similar.

Also, seems to me it's allot harder to find this sort of info on trees in general. USDA zones always leave you wondering if the death blow would be the temperature extreme or the duration. Anyone know a decent online resource for such data?

 

[Shibui]

Pinus pinea is known here as Italian Stone Pine which implies Mediterranean origins. That usually also means heat hardy. They certainly grow well in hot areas of Australia so I suspect your Colorado summers should not be an issue.
As for extreme or duration I cannot offer any insight but I suspect it will turn out to be a combination - exposure to x temp is instantly fatal but prolonged exposure to x+ temp can also be fatal?

 

[ShadyStump]

Thanks but I might have failed to explain what I'm looking for adequately.
A better idea of it's upper range should give me an understanding of it's dormancy needs, and whether or not I can safely fulfill them. Could you tell me what zones they're most commonly found in there?

An upper range of zone 10 or 11 tells me that it can do with little to no dormancy period, and thus I don't need to risk frost damage or death in my unpredictable subzero F winters. Just bring it in with my tropicals for winter.
An upper range of USDA zones 8 or 9, though, I would have to be much more careful about wintering over in my climate to ensure it gets it's dormant time but without freezing too much. Then it might not be worth the effort at this time.

 

[hemmy]

An upper range of zone 10 or 11 tells me that it can do with little to no dormancy period, and thus I don't need to risk frost damage or death in my unpredictable subzero F winters. Just bring it in with my tropicals for winter.

They are used as street trees in coastal SoCal. We had them in Ventura and Santa Barbara, zones 10-11. A member of the SB club had one as a bonsai.

 

[ShadyStump]

They are used as street trees in coastal SoCal. We had them in Ventura and Santa Barbara, zones 10-11. A member of the SB club had one as a bonsai.

Thanks! That confirms for me that they have at least very light dormancy requirements. Do you know if he did anything special for it in winter?

I was able to find a site online where I could roughly cross reference their native range and growing zone.

Plantmaps - Hardiness Zone Maps, First and Last Frost Dates and Much More

A Collection of Planting Zone Maps, Hardiness Zone Maps and Climatology Data for Gardening and Horticulture

www.plantmaps.com

But it's always reassuring to hear a personal account.

 

[hemmy]

Thanks! That confirms for me that they have at least very light dormancy requirements. Do you know if he did anything special for it in winter?

Not for sure, but I don’t think it got any special winter treatment. Probably just on the bench with the rest of the trees.

 

[Flowerhouse]

I have one that I bought in 2021. It has been spending winter in my cool-ish basement under an array of T-5 bulbs. It goes outside in spring, stays out until frost is a threat in fall. It seems happy with this treatment. A test of only one specimen.

 

[ShadyStump]

Thanks! Being unsure if I could keep it happy under my circumstances is the primary reason I don't have gotten one when they pop up as Christmas trees.

 

[Wires_Guy_wires]

The mediterranean climate where I've seen them in varies, but some areas haven't had any serious frosts in 2000 years.
Their dormancy seems more summer related than winter.

 

[Crazy Diamond]

Pinus pinea grows well in central Spain (Valladolid, Castilla Leon) but they like dry cold not cold wet weather

 

[Wulfskaar]

I've got one I've been working with for 3 years. It gets no freezing temps whatsoever.

I'm sure that in nature, they sometimes get freezing temps in Spain on occasion. I believe Spain is where the species evolved.

I think it would be worth a shot, just keep it protected in winter and in a sunny spot. Also, make sure to use a very well-draining soil.

I've documented my journey here but I have a lot more to learn. Since there is so little documentation on this species, please keep a thread on your experiences if you do end up getting one.

 

[ShadyStump]

Thanks all! I'm now fairly confident I can manage giving one what it needs under my current circumstances.