Self watering containers sound like a great way to kill conifers that don't like wet feet.

ahh perfect, this is the information I cant find online for some reason, because I guess no one does it. Who puts a tree in a self-watering pot? :)

So would you recommend just a draining pot? Leave a layer of rocks at the bottom of the pot and have drainage holes?

No rocks - they do not help with drainage - just use a good quality, barky potting soil and with plenty of drain holes.

And be prepared to repot periodically to root prune and replace depleted potting mix. Check out this link for a detailed explanation of how to grow trees in containers.

If you put rocks anywhere it would be in the drip tray so that the pot is elevated above any standing water that may accumulate.

They are supposedly hardy to z3 (or z4 as some suggest) so you should be able to grow them in TO. What you need to consider is the wind; cold wind during winter may cool off the roots too much and also the foliage. Is the terrace totally open to elements on 3 sides? How high up is it? I would consider large pot and very well draining mix - bark based as gardengal already said. During winter, they really need good drainage, otherwise there will be damage. You could wrap them in burlap for the winter to prevent wind from drying them up. Some suggest insulating containers - I never tried and have many large plants in containers but they are not 'high up in the sky'.

I went looking for a bigger container, found 2x of these that are about 20x20", hopefully it'll be large enough to fit a 5-6' emerald cedar. I wish I could get more, but I have to hunt for these at different stores.

The terrace is over the garage on the 2nd floor, so it isnt high at all. I've attached a quick pic of my neighbour across, mine is exactly the same size. I plan to put the containers on the black tarmac on the in front of the fenced portion.

Thank you for all the info, I'll take a look at that container growing thread which will come in helpful. Any other ideas would be greatly appreciative! Maybe a different shrub/plant?

Nice container. Is it resin? Just make sure it has good drainage.

If you need to consider space, you want something that doesn't grow too wide. Anything columnar/pyramidal would be good. You may even grow some deciduous trees, for change of color a weeping beech would be nice - but most will grow tall. How about dwarf fruit trees? You can get flowers and fruit eventually...Or shrubs like hydrangea that could are easily pruned...many could be trained to grow 'flat' - but maybe that's too much maintenance?

it says its a clay fibre pot on the description of the tag, it doesnt have much information other than that. It also says "weather resistant", so I guess it's safe for winter if its sold in Ontario :) It has 1-inch hole at the bottom, I could drill some more in there to ensure better drainage.

Yes, I hope to put in emerald cedars in here, have them grow vertically to add some color to our terrace. I'm very new to all this gardening, we bought 2x Gardenia's Tree last year and they thrived until we brought them inside for the winter, they're survive now but it doesn't look promising. So this year I vowed to get something REALLY low maintenance, so emerald cedars were my choice after some initial research.

Hi, JJ. I saw your request to look at your thread. All the advice you've rec'd is good - nothing to disagree with. If you have other specific questions, I'd be glad to try to answer.

Al

Hey JJ,

I'm looking to do exactly the same thing. How did your cedars turn out?

A very wise plant selection. You can keep them in the same containers for a life time with good root pruning skills.

JJ: I know you ended up using custom-made planters (which look GREAT, btw), but I'm curious about the modifications you did to the fibreclay planters. I just bought the same ones for some holly bushes, only they're in cylinder form, and am working on insulating the interiors to protect the roots from the intense afternoon sun. Can you please tell me the materials you used and the reasoning behind them? Also, mine came with two, 1/2" (1.27cm) diameter drainage holes, but I'm wondering if that's adequate given these planters are approx. 20" (50.8cm) diameter by 19" (48.26cm) deep. Thanks!

P.S. Based on your location—and because I'm such a thoughtful person ;)—I converted my measurements to metric. However after having re-read this thread, I see that might not have been necessary because you used imperial measurements!

Feel free to use imperial in your response. :)

@Sammy The fibreclay planters, I just bought some 1" pink insulation board and used a exacto to cut down for each size and just loosely put into the planter. I then loosely put down some black gardening fabric. I am going to leave my flower bulbs in there to give it some protection from our Canadian cold winters. I kept the original drainage hole and didnt add any extra, the soil I am using is quite porous so I didnt bother, not to mention I didnt fill the entire thing from the top. I filled the bottom half of it with broken styrofoam pieces, one 1" board at the bottom with multiple drainage holes, then fabric and soil.

Thanks JJ! I've been engineering the hell out of these planters (in my mind, of course) since I brought them home two-and-a-half weeks ago, stubborn in my hesitation to ask for advice. Meanwhile, here sit empty planters...

Anyway, thanks again. Hopefully your bulbs and my hollies will thrive in their tricked-out pots!

Hi there , may I ask where you got your planters from? Also what is the pink insulation you put inside the pots? How did your cedars survive the Canadian winter ?

Old thread but for what it's worth - I'm also in Toronto and have kept cedars in pots overwinter in large (24' diameter by 24' tall) resin/plastic pots for years, no insulation - though if i had nice cube planters like yours, I would insulated with the pink stuff too! Best part is if a cedar dies, you can usually find the cheap BC-grown cedars in front of hardware stores for $10-20 each in the spring. Maybe not as hardy as Ontario-grown, but can't beat the price (and I've had just as much luck with BC cedars as Ontario, I think it's luck of the draw!)

I do love those planters though, if you still have the info on where you bought them! Or where the others were made. Many thanks.

If you're trapped indoors with temps in the teens and 18" of snow on the ground, or you're bored, please join me in imagining you have 2 Dixie cups full of water. Put one in a foam cooler to insulate it against cold. Then put the unprotected cup and the cup-in-a-cooler in a freezer set at 0* F/ -18 C. Does the cooler protect the cup from freezing? No. If you were to actually complete the exercise I described, when you wake the next morning, both cups of water will be frozen solid. So, insulating a large planter as shown above does not prevent soil temperatures reaching killing lows if the ambient temperature reaches killing lows. All it can do is slow the rate at which the temperature drops to killing lows. For the unprotected cup, it will likely occur within an hour; whereas the cup-in-a-cooler might take 12-24 hours. The point is, eventually both cups of water will reach an equilibrium with ambient temp within the freezer, 0/ 18*.

The only situation where insulation can be relied upon to be helpful is when there is an extraneous source of heat that can be captured within the pot/soil mass. 2 examples:

A) You live in a high rise, have a balcony, and need to protect a plant's from freezing low temps. In this case, you would insulate the pot bottom, 3 sides, and have maybe some ground Styrofoam you can pour over the top of the soil and cover so it won't blow away. So you have a pot insulated top, bottom, 3 sides. Situate the uninsulated side of the pot against the outside wall of the building so heat can conduct from the wall into the pot where it can be "trapped" by insulation. If you insulate entirely, you prevent extraneous heat from entering the pot and end up with another version of cup-in-a-cooler.

B) You have a plant hardy only to a zone higher than yours and you want to protect it by keeping it in an attached garage over winter. In this situation, you can do either of 2 things. 1) You could cut the top off of a cardboard box, turn it upside down, and cover the plant. The box will trap geothermal heat rising through the garage floor and keep the plant as much as 20* warmer than temperature outside the box on the coldest of days/nights. 2) you could wrap all for sides of the pot with insulation (but not the bottom). Then, set the pot on the garage floor and cover the top of the soil with cardboard or newspaper relieved around the trunk stem of the plant. This also traps an extraneous heat source - the geothermal heat rising through the floor - in the soil mass. If you insulate the bottom of the pot in case B, you shoot yourself in the foot.

BTW - eastern white and western red "cedar" are not really cedars. Thuja is among the 7 or 8 genera with trees referenced as "cedars". Thuja plicata and Thuja occidentalis are arborvitae trees.

Al

@JJ I know this thread was originally started 5 yrs ago, but I'd love to know if you have a "where are they now" update :P

wow its been 5 years alrady :) we just finished our terrace renovation and have the original cedars still with its original soil. I am looking to top off (recharge) the old soil with some of the same material/mix along with new mulch.

I ended up having someone create 2x custom planters (preassure treated with insulation) that fit the 6 cedars. The original planters that I bought I couldnt find enough of them, so I used them just for flower planters, but they didnt hold up very well.

I had a little browning (as you can tell in the 2021 pics) but I had to disconnect my drip irrigation system for the renovation, so they need watering, but you can compare the tree heights from 2016 to 2021, they grew significantly within the planter!

Before Pics 2016

After Terrace Reno 2021

I was totally going out on a limb and not expecting a reply, but this is great! What a pleasant surprise. Thank you for sharing the update. Your terrace is beautiful and the plants are thriving. I’m sure the slight browning will recover, especially now that we have some cool weather and rain. I agree with you on those original 2 planters…I have 2 similar ones (bought at Lowe’s) that didn’t hold up after one winter. I moved out of the city a few years ago so my place probably gets colder, but my planters cracked and crumbled at the bottom! I ended up cutting the entire bottom out and putting them directly in the ground. Seeing how your cedars made it after these years, I’m going to give a couple of zone 3 globe cedars in large planters a go! Thank you!

So unfortunately two of my cedars didn't make it through the winter along with a third and fourth having some browning in a few branches.

I had to pull one of my tallest out, I figured it was time, it's been 6 seasons since I started the project and had ample warning even with the 5-1-1 mix that they would last around 5 years in containers, so wasn't surprised. 

Ill be replacing the 2x with new ones this year and will most likely have to replace the other 2x next year. Time for me to read up on my previous posts on where I got all the materials lol.

Sorry to hear a couple didnt make it through the winter. Have you considered trying something deciduous instead? Like a redtwig dogwood? They are fast growing and nearly indestructable, but l guess it doesnt give you the same level of privacy. Funny enough, work has reassigned me to Northern California…bye bye snow and hello to zone 9/10 drought and fire prone climate ^_^

Yes! Been considering other tree's to plant in replacement of the Emerald cedars. But unsure if I'll be able to get 5 years or more depending on the type... But Hard pass on deciduous just due to cleaning up leaves ᾒ3

Ah grass is always greener. Give up one for something else. Lol

Yup. Very excited to learn about drought tolerant plants for a 2x3 container….as that’s all I have to work with at my new condo! (Coming from a 35x100 yard *sniff*).

Getting evergreens to survive the harsh canadian winters in containers is a challenge. Was told by my landscape design prof that even though emerald cedars are rated to very low zones, they must be planted no later than May in the landscape and never be able to dry out over the summer. Something about the plants need sufficient time to develop resilience and the roots get access to water below the frost line over the winter since they do not go fully dormant like deciduous. Hence you see these dead emerald cedar hedges all over toronto after one growinf season because the owners put them in June or later. I imagine a really deep prolonged freeze in a container would be very tough on the plants. Not sure if you rigging up a heating system when temps hit -20 or something would be a way to hack nature 😂