# Why don't cold-hardy ever green plants grow in northern climates? **URL:** \ **Category:** Factual Questions\ **Created:** [September 5, 2014, 4:36am UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552 "2014-09-05T04:36:55Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\ **Post date:** [September 6, 2014, 10:49pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/21 "2014-09-06T22:49:59Z")
Sabal palmetto is zone 8. That’s what I call a northern climate. Some sources say it can grow farther north, but nowhere where it gets below zero. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 6, 2014, 11:23pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/22 "2014-09-06T23:23:57Z")
> [@Contemplation](#): > > So you’re also saying photosynthesis can only happen above freezing? The process of photosynthesis needs liquids to work properly, but some plants have ways of keeping their internal fluids unfrozen when the temperature outside is below zero. That said, the rate at which \*anything \*happens inside a living plant will be greatly reduced during freezing conditions, even if the plant itself remains unfrozen. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [September 6, 2014, 11:54pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/23 "2014-09-06T23:54:38Z")
> [@Mdcastle](#): > > Sabal palmetto is zone 8. That’s what I call a northern climate. Some sources say it can grow farther north, but nowhere where it gets below zero. There is a form of Sabal palmetto ([S. ‘Birmingham’](http://www.chillypalmtree.com/SABALBIRMINGHAM.html)) that grows in Oklahoma, Virginia, Maryland and southern New Jersey. It has withstood subzero temperatures (reportedly, -11F in Oklahoma). I have a small Sabal (name?) which survived our -19F winter low up against the brick wall of our house. I’m under no illusion it will get big enough to be a full-fledged trunked cabbage palm, but it’s fun to try. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [September 7, 2014, 12:20am UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/24 "2014-09-07T00:20:09Z")
> [@Jackmannii](#): > > There is a form of Sabal palmetto ([S. ‘Birmingham’](http://www.chillypalmtree.com/SABALBIRMINGHAM.html)) that grows in Oklahoma, Virginia, Maryland and southern New Jersey. It has withstood subzero temperatures (reportedly, -11F in Oklahoma). [Sarracenia](http://en.wikipedia.org/wiki/Sarracenia) grows in the Pine Barren Forest in New Jersey. ---
**Author:** ![EdwinAmi](https://avatars.discourse-cdn.com/v4/letter/e/5fc32e/32.png) [@EdwinAmi](https://boards.straightdope.com/u/EdwinAmi)\ **Post date:** [September 7, 2014, 4:31am UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/25 "2014-09-07T04:31:35Z")
are you seriously asking why plants that can be grown outdoors in an area don’t all spread out and naturalize in said area? Of course most of them don’t. A plant becoming naturalized involves far more than just whether it can handle the climate in the area. There’s all the other issues, how _well_ does it do in the climate? How does it do in competing for sunlight compared to the local plants? Ditto with growth rate and competition. How is it affected by the local pest bugs? How is it affected by animal predation? How well does it seed-disperse in the area? etc. etc. Some plants, of course DO naturalize in an area when introduced, and some even become invasive. Here in the northeast, empress trees and wisteria are very commonly seen specimens whose species are not native. Luckily, as invasive as they are, they’re also quite pretty. The South is being over run with kudzu. etc. etc. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [September 7, 2014, 5:14am UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/26 "2014-09-07T05:14:29Z")
> [@EdwinAmi](#): > > are you seriously asking why plants that can be grown outdoors in an area don’t all spread out and naturalize in said area? I believe so, but he was polite. 🙂 ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [September 7, 2014, 5:15pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/27 "2014-09-07T17:15:43Z")
> [@EdwinAmi](#): > > are you seriously asking why plants that can be grown outdoors in an area don’t all spread out and naturalize in said area? **Moderator Note** **EdwinAmi** , you’ve already received a warning in another thread for insults. I’m just noting here that this kind of remark is also inappropriate for GQ. You need to change your posting style if you want to continue to post here. Colibri General Questions Moderator ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [September 7, 2014, 11:58pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/28 "2014-09-07T23:58:12Z")
The north had a recent ice age affect it, the trees that have repopulate it are those that do well in the area. Suppose a bird eats the fruit from an evergreen and flies a long distance … from the southern hemisphere (Australian alpine area ? where there were no conifers… and importantly, no snow loving herbivores… ) to the north and the seed is deposited there in among the deciduous trees… So there is this small tree growing above the snow… the only bright green leaves in a great forest of totally bare trees. A herbivore , a deer, moose,elk, whatever, is wandering along, looking for exposed grasses in the snow drifts, and sees a bright green bunch of leaves… it simply eats up tree up… For the evergreen to survive it would have to have safety in numbers. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [September 8, 2014, 2:28am UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/29 "2014-09-08T02:28:21Z")
> [@Isilder](#): > > Suppose a bird eats the fruit from an evergreen and flies a long distance … from the southern hemisphere (Australian alpine area ? where there were no conifers… and importantly, no snow loving herbivores… ) to the north and the seed is deposited there in among the deciduous trees… Perhaps an African Swallow. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [September 8, 2014, 3:27pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/30 "2014-09-08T15:27:35Z")
> [@carnivorousplant](#): > > Pine trees are a common plant in the Southern USA. There aren’t many in New Hampshire, I learned upon traveling there. I’ve also seen how badly they fare in a heavy snow or ice storm. I wonder if having foliage in the Winter is a detriment in cold climates. Well, there’s ‘pine trees’, in the sense of any evergreen tree with needles, and there’s pine trees that are true pine species (in the genus _pinus_). Spruce and fir have needles but they’re not strictly pines; at higher elevations in NH it’s all spruce forest. Eastern white pine does grow in NH at lower elevations, they’re fairly common in disturbed areas and edges but they get outcompeted in the middle of an established forest. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [September 8, 2014, 4:37pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/31 "2014-09-08T16:37:20Z")
> [@Contemplation](#): > > So you’re also saying photosynthesis can only happen above freezing? Carrying of nutrients into the leaf or needle, and out again, so photosynthesis can do its work, needs fluids. The colder the environment, the more danger that water medium will freeze. So during winter months, plants have to reduce the amount to which they are water-saturated, or they will freeze, doing damage at the cell level or worse. Wide flat leaves are more prone to cracking in the wind, etc. The extremely low humidity may mean leaves will dry out faster than the very minimal water can replenish the leaf. Damage to leaves in winter can be difficult to repair even once the plant warms up. Pine needles are less susceptible to rips, tears, and breaks. If some roots are above the frost line and get frozen, then there is less root for the plant to acquire more water during the winter. Even grass, (I think) the leaves die off, and the root system sends out new shoots in the spring. Green leaves in winter will be a tasty treat for local animals, so a plant needs something obnoxious (as pine trees have) to discourage grazing. So yes, in most temperate climates, it is simple for the plant to go dormant and shed its leaves, and re-grow them in the spring. There is minimal benefit in trying to operate photosynthesis during the cold, and substantial risk of damage. Remember too, that every plus has a minus, every strength has a cost in evolution. Evolving systems to prevent leaves drying out means a plant devotes resources to growing parts that deciduous leaf-shedding plants don’t have to. The plant will lose in the summer to plants that can ignore the winter problem and grow much faster in the warm times. The only place this is an advantage is where the summer is too short for the deciduous pants to overcome the evergreens’ head start. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [September 8, 2014, 7:03pm UTC](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552/32 "2014-09-08T19:03:30Z")
> [@Isilder](#): > > The north had a recent ice age affect it, the trees that have repopulate it are those that do well in the area. > > Suppose a bird eats the fruit from an evergreen and flies a long distance … from the southern hemisphere (Australian alpine area ? where there were no conifers… and importantly, no snow loving herbivores… ) to the north and the seed is deposited there in among the deciduous trees… > > So there is this small tree growing above the snow… the only bright green leaves in a great forest of totally bare trees. > > A herbivore , a deer, moose,elk, whatever, is wandering along, looking for exposed grasses in the snow drifts, and sees a bright green bunch of leaves… it simply eats up tree up… For the evergreen to survive it would have to have safety in numbers. Not sure about the last point. As I mentioned, in New Hampshire, White Pines are the first trees to grow on disturbed areas, so they’ll quite often be growing all alone (or with no other trees right next to them). My guess is that most herbivores aren’t very fond of pine resin. [Previous page](https://boards.straightdope.com/t/why-dont-cold-hardy-ever-green-plants-grow-in-northern-climates/697552.md?page=1)