You don't say what your zone is - or at least a general idea of where you are - and mention only spearmint. Most spearmints are hardy to zone 5, some down to zone 3.

I don't grow anything in pots so I can't help you there. Where I live, a clay pot left outside over a winter would pretty much be toast. But my zone appropriate perennials planted in the ground survive harsh winters - oftentimes extended periods of 20 - 30o below zero with wind chills down to minus 45 - 50. Snow cover is always a bonus since the snow is a good insulator.

Cold enough, yes, anything will die. That is why Antarctica is notoriously barren. However, most place don't get that cold.

So the two variables are how cold it tends to get outside where you are, and how much cold a particular type of plant can stand. Spearmint can handle a fair amount of cold. I've kept it outside in a pot in Philadelphia, so it can be done.

where are you ..

the definition of perennial.. is that it lives more than one year ... so no.. they dont all die because it gets cold ...

you define how cold a plant can take.. by looking up its zone...

then you compare that to your zone...

so if you are growing a plant.. that can handle a z5 winter.. and you are in z7 ... it has the potential to live forever ... though i dont know.. with you in charge.. lol ...

if i choose a plant that is only z7 hardy.. and plant it in my z5 MI ... it will act as an annual.. and probably die in winter ...

pots completely change everything ... as well as if the balcony is in wind or in sun .. etc ...

even if you are in z7 .. but have 20 to 40 mph winds all winter.. plants might die ... but is wont be.. because they are too cold ...

there is a container forum ... and there are some peeps who do great things on roofs ... if you could track them down ... you could learn a lot about growing on your balcony ...

hope you have a sense of humor... and good luck
ken

Mints are pretty tough and would likely handle most winters in temperate U.S. climates in a clay pot - unless allowed to dry out. This doesn't mean they'd automatically be fine over the winter in Bismarck, North Dakota. But Memphis or Pittsburgh winters probably wouldn't kill potted spearmint.

Awhile back I had a hardy cactus seedling (an Opuntia) in a small pot. It was spindly and unhealthy-looking, so I left it out on the patio over the winter thinking that would be the end of it. I was very surprised to see a new shoot come spring, and once transplanted into the border it grew happily for a few years until I got tired of being stuck by its spines and nasty little glochids while weeding, and uprooted it.

Mints are like cockroaches. They would probably survive nuclear devastation and keep on trucking.

Marigolds, zinnias, impatiens and other annuals generally sprout, grow, bloom and die over the course of the season once they're nipped by frost.

Planted in the ground, mint, daisies, peonies, lilies and other perennials generally sprout in spring, grow, bloom and go dormant when cold weather triggers them the time is right. The following season they repeat the cycle, often year after year. There are peonies in my garden that have been here 40+ years.

Planted in containers/pots, perennials need to be hardy to at least 2 USDA zones colder than your own in order to survive the winter. For your mint to survive the winter in a pot outside, it would need to be hardy to 2 USDA zones colder than where you are. The pot should be set close to the house foundation--on the deck is pretty exposed to harsh weather. Mints tend to be pretty tough, however, and can actually be borderline invasive.

Perennials are rated by growers to be hardy in specific USDA weather (hardiness) zones. For example, Siberian iris is hardy to Zone 3, I'm in Zone 6a so it will survive in my garden in either the ground or a container.

Hello to all of you, and thanks for your responses back.. Sounds like I need to mention which zone I'm in for perspective.. Just GoogleImaged "climate maps" and got a few different ones.. Overall though, it appears I'm in z4, and bordering z3 (NW Arkansas).. It's going to be 17 here overnight (colder than usual), and then drop in temps the following night even colder.. I'll be amazed if the Spearmint survives, but hope it does...!
PS If there is a climate map somewhere on this site, please sent me a link if convenient..

Here's the current USDA Plant Hardiness zone map. Arkansas includes zones 6b to 8a. Type in your zip code and you'll find out which of Arkansas's 4 zones you're in.

http://planthardiness.ars.usda.gov/PHZMWeb/

Arkansas ranges from about 6b to 8a. Zone 3 gets to 40 degrees below zero (more like northern North Dakota). Should be okay in a container all Winter. My oregano over winters in a container outside w.o. problems.

P.S., eric oh, I decided to leave the Opuntia but wear gloves when weeding.

This post was edited by njoasis on Tue, Dec 30, 14 at 19:55

skyclad - are you at a high elevation? As mentioned above, Arkansas isn't normally included in Z4 USDA zone maps. I'm in northern CT just a couple miles south of the MA state line and I'm Z6a. It's 26 here at the moment and expected to drop to 16 tonight so colder than where you are.

I'm looking at my USDA Zone map and I don't see anything showing up lower than Z5 in what I think is Arkansas.

Keep in mind that a perennial like mint will most often simply go dormant in extremely cold weather. That means it's asleep and should "wake up" as soon as the soil begins to warm in spring. Plus gardeners tend to be optimists.

After viewing the map on this site you guys sent me (thanks), it looks like I'm right on the border of 6b and 7a........just about exactly on the line.. I have no idea what kind of map I was looking at earlier, so thanks for the real one!
We are a bit elevated where I live in, but it's only around 2,000 ft. or so, possibly some less.. But 17 degrees tonight is definitely on the low side of our temp range..

skyclad - perennials in Z6 don't even blink at cold weather in their comfort zone--they just go dormant and wait 'til it warms up again.

If gardening teaches nothing else, it teaches patience and acceptance that Mother Nature has been keeping the planet green for a few millennium and chances are she'll keep doing so a few more so you've no need to worry about it.

Gardening lesson #2 is that you shouldn't give up on anything until you know for sure it's dead. They're not called "perennial" for nothing. My Lenten roses begin blooming in March every year--they've got buds on them even now. Last thing to bloom for me every year is Tricyrtis/toad lily in October. The bees love it. I get a kick out of watching the bumblebees gathering nectar from the blooms upside down from the bottom.

The mint should be fine, but you may lose the pot. Freeze and thaw not great for terracotta (clay) pots.

The mint should be fine, but you may lose the pot. Freeze and thaw not great for terracotta (clay) pots.

The repeated freeze/thaw cycle can be death to even tough perennials in pots that are above ground - if the temps have been very low with a quick warm up with rain, it can't drain through the frozen soil and will freeze as ice around the crown of the plant killing it. I have lost perennials this way in the past, (zone 5) and anything perennial in pots gets put into the ground - taken out of the pot - to overwinter insulated in the ground.

As a NW Arkansas'er, most hardy plants will survive the winter in pots here. As mentioned the pots themselves may take more wear than the plant (clay cracks, plastic turns brittle, etc). Certainly spearmint (other than drying out) can't be killed without poison in this area, if it was left outside from early fall (not suddenly thrust out in midwinter) through spring.
Here, most people forbid planting mints in the ground, because they take over the world...it's common to leave them in pots or contained in pots sunk in the ground.

I grow chocolate mint in an outdoor pot. It has survived 4F with no problem.
MBWD

This post was edited by moistbutwelldrained on Wed, Dec 31, 14 at 11:13

Thanks to all of you and your feedback on the perennial issue! Overall, sounds like it will be ok.. No doubt I'll be back with more very basic questions about this at some point.. Thanks again for all the help!
S

skyclad - Best of luck & happy to help!

skyclad don't put that mint in open ground--it'll take over...it's a very agressive *underground runner*!