perennials in containers, year round

I'm pretty new to gardening, and was wondering about this topic- is it possible, in coastal New England, to use perennials in containers and leave them out, year round? . I have a big rock ledge in my yard and I wanted to put a good sized hypertufa container on the top of it with some shade plants- probably hosta, ferns, etc. It's a mostly dappled shady spot, and there doesn't seem to be many shade annuals that appeal to me for that spot. I used some perennials last year in other containers, but moved them into the ground at the end of the season. I'd rather not do that again, as I'm kind of running out of space in the garden. Also, space is at a premium in the garage, so moving a bunch of large containers in there for the winter is also not an option.

Is this even possible, or would the plants have no chance of surviving the winter? If it might be possible, are there some plants or small shrubs that would be better than others to try it with?

I would be hesitant to say yes in your climate. The roots would be pretty vulnerable to freezing. Maybe someone with cold weather experience will come along.

I live in zone 6 and so far the hosta growing in shade in large pots without protection come back every year and even increase. I would say, give them a try.

The type of plants you want to look for are ones that are hardy to a zone or two colder than you, having things in containers effectively reduces their hardiness a bit, so things that are only hardy to your zone may not make it through the winter.

Thanks for the responses. ecrane, that was gonna be my next question- whether or not to select plants a couple zones colder...which I think hosta and ferns are. Hmm...

I read about insulating the containers with bubble wrap for added protection- would that actually work? It doesn't seem like bubble wrap could do very much...any other ways of giving the container some protection? Tipping it over into the ground wouldn't be do-able either, considering it's pure ledge under that area.

Noreaster, one possible solution would be to group your containers together for the winter before the ground freezes (probably November for you?) and surround them with hay bales or bags of leaves. Then top them off with a layer of leaves and with the snow you receive over the winter as extra insulation, they should survive. Hostas should do just fine with this method - the worst enemy for any plant "containerized" is 'winter wet'. We're Zone 6a and we just tuck the containers in under the eaves of the house to protect them and they're still going strong after three years - Hostas, Heucheras, Ferns, Brunnera and several other perennials planted in them. We also have some hypertufa trough containers with Sempervivums planted in them that are fully exposed to the 'elements' all winter and thriving.

Debbie

Debbie I do the same thing. I have a lot of hostas and ivies in containers. Just group them together in a protected corner behind the house and they do well. In fact they look really great this year!

Juanita

Debbie and Juanita have good ideas there!

Nor'easter,

Any plant that is hardy to the north of you (say hardy to zone 3 like Hosta or lillies) will be fine in a container.

It's summer here, the plumeria are in bloom.

That's very pretty, Dale. Man, part of me wishes so bad that I could live somewhere at least mildly tropical. Well, for maybe half the year anyway! ;)


So it sounds like hostas would be a fairly safe choice..I definitely have lots of leaves to bag up that I could use to surround the container if need be.

Here is the spot (red x) that I'd like to do something with....there is a Barberry (?) bush in the front there, and then some kind of small, non descript tree directly behind it. When it leafs out, it basically melds with the Barberry, which I guess it ok...I just thought it could be more interesting. I was thinking the broad leaf of a hosta would contrast with the small Barberry leaves better. If anyone has any better ideas, please let me know.


This message was edited Apr 27, 2007 10:54 PM

The view from the top....it's also where I deposited all the rocks I dug out of the rest of the beds I put in. I'm sure there are plenty more underneath these, which is why I think I just want to go with a container here. I use the gravel path next to the daylilies, and also the back pathway that runs the length of the yard.

A pic from last year.. I guess when the daylilies are in bloom, they would kind of obscure it, but I do still use that little gravel cut thru.

My husband will probably freak out if he sees me clearing out anything else, so whatever I put there had better be really nice!

The cobalt blue pot that I spied in the last photo makes a beautiful contrast with the daylilies! Your land looks wonderful with all the rocks defining areas.

That's one thing I remember clearly about my grandmother's wonderful garden in Maine - there were big rocks or areas defined by rocks defining different areas. That was not only coastal; it was on an island! But I think Wells was on the way. I don't remember her having containers, though.

But I was wondering more about the perennials in containers. From my experience, you need to remember to FEED them. They won't be getting whatever natural nutrient cycles go on in the ground. I had coreopsis which outgrew its container, so I split it in two, and had one tiny sliver left over, which I tucked into a garden bed. Well, the sliver took off and went bananas, while the two containers died. Moral: there must be more to getting perennials to grow in containers than just what kind of plant it is.

Hmmm.

xxx, Carrie

Remember to add controlled release fertilizer as you mix the soil for the container. You can get some that will feed them all summer.

Good plan, pirl, how about waterzorb or whatever those crystals are called?

xxx, Carrie

Well, the guy at the garden center kind of talked me out of it, saying the roots would surely freeze. I dunno, it may be worth a try as long as I'm not particularly attached to the plant(?) I try it with, I guess. I was also wondering if there was a way to make a container with a sort of removable liner so that if you wanted to bring the plant in, you could just scoop it out but leave the container..is that crazy? Those big hypertufa containers are so heavy, even without soil and plants that I can't imagine moving one with plants in it. I know there are lighter weight containers that might work, but I haven't seen any that I thought would fit in well with the rocky landscape.

I guess I could also remove those trees that are there now, and the pile of rocks, and then excavate and see how much earth is there before I hit ledge and possibly plant something in the ground..oy, what a job that is, though!

Do those water crystals do a good job? I have to leave for a week in July and I'm dreading it because I know my husband can't be trusted to water my plants.

I've never used them, although I have a jar on the bureau. LOL. Those droids that work at the garden center only know what's worked for them already. I got interested in perennial containers when I noticed some of the things I didn't get around to planting survived the winter if they were in big enough containers! High Country Gardens has an article on their site about perennial containers!!!
http://www.highcountrygardens.com/library/view/article/297/
Pshaw on the garden center guy! Find out what's cold hardy in British Columbia, or Saskatchewan(sp.?). I'm not sure about the taking it out of the container every 2 - 3 years to trim the roots part.

xxx, Carrie

You can put your plant in a nursery pot and then put that into a pretty container so you can bring the plant inside for winter but start bringing in plants before cold weather is upon you or they risk losing their leaves. Many do anyhow because homes are not as humid as outdoors.

carrie, I know what you mean about people that work at garden centers...they don't always know everything...though I do expect them to know more than I do, which is still precious little, lol.

I was in there a week ago and asked that guy about the container thing and also I had a question about one of the plants I bought last spring that apparently was the only thing in my garden that didn't make it thru the winter. Well, I didn't really feel like he gave me a good or a thoughtful answer about it, so I decided to ask the same question to another employee there the next time I went back, which was a few days later. So I go in and ask my question to the woman working....she seems to not know anything about the plant (brunnera), so just as she is pulling out a big plant encyclopedia to look it up, the guy from earlier in the week walks in the door and she calls out my question to him. It must have been like deja vu for him, and I was mortified, lol. It was like saying, yeah, that's right, I didn't trust what you told me so I thought I'd ask someone else.

I think you deserve applause for asking about the Brunnera again. It shows you really are trying to find out why it didn't make it through the winter. Embarrassing? Sure. It should have been their embarrassment, though, not yours.

Agreed, everything.

Nor, I'm worried about your entire house filling up with tender plants (like mine does)! I think you shouldn't spend the family fortune, but you should do a little research and figure out what plants are hardy to zone 3 (?). Put the absolute best dirt (or non-dirt) in there with drainage etc., maybe set it up like an Earthbox (there's a forum for that too). Give a plant or two your best shot (soon, so it'll have time to hunker down by winter), and go for it. Ask T-plant about earthboxes and weezingreens about cold climates. Maybe you could wintersow (another forum to check) your chosen perennial so a. you wouldn't have to spend the family fortune and b. you wouldn't be limited to that stupid garden center for choices.

You don't have to practice on that fairly inaccessible location in your picture; practice with some heuchera near the house.

I don't really know what I'm talking about but I can't help blithering on...

xxxx, Carrie

Noreaster - were you asking about cold-hardiness issues? or just overwintering perennials in general?

Al

tapla, you mean my original question? I just wanted to know if it was possible for things in containers to survive New England winters. I have some books on container gardening, but they don't address that directly.

Pirl, yeah, I really do want to know what went wrong with those two brunneras..I think I have the right sort of conditions for them to do well so when the guy just kind of shrugged it off by saying, "who knows, it's a plant", that wasn't too helpful, because I'm trying to figure out if I should give it another shot this season, and of course, what to do differently.

I think I will give it a shot with a hosta, and maybe I can snag a cinnamon fern from my FIL, since he has tons of those. I know they don't transplant well, but I did one last year and it's doing fine. Plus, it's free :)

Carrie, I know, I have a really small house and one car garage that is already full of junk...I really can't get in to bringing lots of stuff inside- my husband would hate that, too.

pirl, I am doing what you suggested. I have planted a couple of things in a plastic liner pot??? and put it in a pretty pot. Then can lift it out when needed. Also planted a per. or two in a 2 gal. pot in center of large pot with other plants in the soil around. that way I can lift the pot out and replace with something else if I want. I have planted about 10 pots and have 6 or 7 more to go. In several I just divided some perennials growing in the garden, so didn't have to buy something Most of the pots have drippers or something of that nature and a timer.

Donna

Excellent! Send photos when they bloom.

I'm sorry you didn't get the info you needed at the garden center- generally those jobs are like any other retail job, and you're not going to get Horticultural degree type info from someone making 9 bucks an hour for the summer! (If that!) Next time ask for the manager if you feel you're getting employee approximations.

But even then, they may not know. Many garden centers don't grow or overwinter their stock. They buy and clear out at the end of the season. So they just don't have any experience with what you're asking.

That said, I work at a small nursery in NE CT that overwinters their stock. At the end of the season they make small hoop houses out of white greenhouse plastic and pvc pipe arched into wooden frames around the pots. After the plants are packed in close together, and the plastic is covering the hoops, they screw in lath strips to the wood frame to hold the plastic edges down, and then lay a layer of sand around the edge to weigh down the white plastic further, and keep out the mice. (Mice are a huge problem. They like the shelter and the easy meals.) Depending upon the plant, sometimes they shovel soil in between the pots before covering for more insulation. Hostas do remarkably well in pots year over year- brunnera, not so much. What kills the brunnera is not necessarily the cold, but soggy soil- without much air circulation, the roots rot. It's a real crap shoot- you never know what's going to survive until you pull off the covers. And the timing of that is key too- you don't want to wait too late in the spring and the moisture inside starts to condense and rot the plants....on & on.

But if you have room in your yard, you should try to make a small hoop house and hustle your plants in at the end of the season. I'm not sure when that that would be for your zone- you may want to find a grower in your area and ask them when they shut down for the season. Or just keep an eye on the temperatures, and go with your gut. Keep the containers on the dry side before tucking them in. Repot & give them fresh soil every other season, if not every season to keep the medium light. If you want to be super careful, heel them in or pack soil around the pots. Use the white greenhouse plastic that you can order from greenhouse supply places online. Sometimes they sell it by the yard, so you won't have to commit to a lifetime supply.

It'll be a big investment the first time, but the wooden frames & lath strips will last a few years, and if you're careful with removing the plastic in the spring, you could get 2 winters out of one piece.

That's how some folks do it. I hope this info helps-

Thanks for explaining that- I had been wondering how the nurseries kept all those unsold potted plants over the winter. Unfortunately, I don't think we have room in the yard for a structure like that...or possibly we do, if it was small enough. Hm, I guess I'll have to think about that some more. Does it matter if it sits in the sun or shade?

Nor,

I thought your original wish was to have these containers in place year-round. If I were you, I'd just try it with some Canadian or Arctic plants.

I always find perennials in pots that didn't make it into the ground! This year it was a hosta and a bittersweet vine. Last year it was alyssum saxatile.

Did you Dmail weezingreens? I think she's zone 3.

xxx, Carrie

I know, I really would prefer just to keep them in their pots and leave the pots in place....then presto, in the Spring have live, pretty plants. I guess I am just lazy, lol. Garage space is extremely limited, as is actual garden soil, but I guess I hadn't considered erecting some sort of temporary structure that I could move things into like that. I guess if I did that, I would do as Pirl suggested and plant things in a inner nursery container, and just remove that from the heavy hypertufa one.


I'm still really flip flopping about what I would like to see in that space. I saw a big leaf hydrangea today with white blooms and dark leaves that I thought could look nice in there- but I already have one macrophylla hydrangea in the ground that I went to great lengths to winter protect this year (covered it in leaves in a wire bin)- not sure I want to do that again...though, if I could just pop it out and put it somewhere....

I hated the leaf thing with the hydrangea because they got all compacted and some of the branches were damaged, and it was painstaking to remove the leaves without knocking off the buds I went to such great effort to protect. So, gotta think about other methods of winter protection for that one, anyway. Or just let it go and see if it blooms without the protection....

No, I haven't d-mailed anyone yet....been busy with other things so my perennial container idea is sort of on the back burner for now.

This message was edited May 15, 2007 11:26 PM

This message was edited May 16, 2007 8:39 AM

It would be best to place your mini hoop house in a bright location, but it doesn't matter much, really. The white greenhouse plastic allows some light to penetrate. You could make it as big or small as you like.

PS:If you get tired of wrapping & coddling your Nikko Blue (or whatever it is) hydrangea every year, you might want to get an Endless Summer hydrangea. They're hardy to zone 4 and since they bloom on old and new wood, there's no wrapping & praying (and counting every bud!). Nobody likes to just heave a shrub into the compost, but those Nikko Blues just aren't worth the effort if you're not in a temperate location. (Just my opinion, heh!)

Yes, I learned about Endless Summer after we bought and planted ours- Merritt's Supreme. I don't even know why the nursery here sold it, when it is only rated to zone 6. Although, by some new zone maps I've seen, we may be in zone 6, I dunno. The hydrangea was a gift from my mom, so I kind of compelled to try to hang on to it for a while at least. We'll see how it does this summer. Couldn't I erect my mini greenhouse right over that thing? That would almost be easier than mounding on the leaves and then taking them off again!

What exactly does a plant require during the winter months, anyway, as far as air, light, and water go?

Ha! You could erect a mini greenhouse over it-that might be worth trying. Except it might be bad for air circulation. In ground care is very different from container care. Some folks wrap in burlap- as opposed to the buried in leaves approach. That allows air & rain while still giving some protection. Maybe someone who's done it that way will chime in- I haven't done either, so I hesitate to recommend anything for that.

You can probably tell right now how your hydrangea's going to bloom this summer. Go check out the buds. If they're dry and dead looking- well, that's not a good sign. If they have color and are firm & healthy, then it's promising at any rate.

You want to hoop house the plants when they go dormant for the winter. Generally around Thanksgiving or so, temperatures depending. Once they're in, you don't pull them out until spring. The first week in April is about right for NE CT, you might have to wait a bit longer. You might want to find a local grower and ask them what their timing is. Or watch other people's gardens closely! Generally you're just giving them protection from wind and cold while they're dormant. Wind can dry out your potted plant, and cold can damage/kill roots.

The plants will get some light through the plastic. Enough to keep them warm & wake them up in spring. You want your hoops about a foot or two higher than the top of your pots for decent air circulation. When you put them in, you want the soil to be on the dry side, but not totally dry. If you heel them in, or pack them with soil, they can get moisture from the bottom holes of their pots if they need it. Leave evergreens with their foliage on, hostas and other re-growers get cut down to pot level.

When I was researching how to winter protect my hydrangea last fall I found another site where a guy recommended essentially building an igloo around the plant, using black garbage bags stuffed with leaves as the building blocks. Which again confuses me because as a beginner, I don't have a grasp on what a plant needs during it's dormant months. How could something stay alive in a garbage bag igloo?? But then, how could my plant stay alive under all those wet leaves with heavy snow on top? I think the weight is what caused me to lose a couple branches...I guess I should have tried to make the plant more like a tight column before burying it...mine is a bit of a sprawler.

I also have to admit that I don't quite get how the buds work. It had buds of some kind all up the stems (canes?), but from what I can tell by looking at hydgrangeas at the nursery, you only get a flower at the end of each cane. So, the lower buds I saw were just leaf buds? So, I did lose the buds at the tips of a few canes, plus those two branches that broke off completely. But the good news is that I just went out and peered into some of the leaves and I saw the beginnings of about 3 or 4 flowers. Here is a pic from last November.

Noreaster, I don't live in New England and don't have the snow cover you do in the winter. But we had the worst winter in a decade this past winter, and here's what came up despite the snow and cold. Columbine, clematis (3 kinds), Jacob's Ladder, chives, hostas. I've had lilies, tulips and other spring bulbs, ferns, astilbe, a climbing rose and a peony come back after overwintering. I've even had water garden plants come back that were frozen in a solid block of ice in the container. With a little protection you can plant a lot. The best place for mine over the winter is close to the building (I live in a high-rise apartment building on the 6th floor). Give it a shot!

Here's my Social Climber after overwintering it one year.

Noreaster - FWIW, regarding cold-hardiness/tolerance: Commonly, each species of plant has a general range of cold-hardiness, but we know this does not apply to all plants equally within the species. Within species and cultivar, cold-hardiness is genetically determined. That is to say that a plant that is propagated from cuttings or tissue culture will have the same ability to resist cold as the parent plant. Plants cannot "develop" a greater degree of cold-hardiness by repeated or prolonged exposure to cold, even after 100 years (trees).

If we pick any plant at random, it may or may not be able to withstand freezing temperatures. The determining factor is the plants ability to prevent freezing of bound water. Bound water is the water inside of cells.

There are actually three kinds of water to consider when we discuss "freezing". The water held in soil - When this water freezes, and it can freeze the soil mass solid, it doesn't necessarily kill the plant or tissues. Then there is free or unbound water, also called inter-cellular water. This is water that is found in plant tissues, but is outside of living cells. This water can also freeze solid and not kill the plant. The final type of water is bound water or intra-cellular water - water that is bound within cell walls. If temperatures drop low enough to freeze this water, the cell/tissue/plant dies. This is the freeze damage that kills plants.

Fortunately, nature does have an antifreeze. Even though temperatures drop well below freezing, all plants don't die. In hardy plants, physiological changes occur as temperatures drop. The plant accumulates solutes (sugars, salts, starches) in cells and moves water out of cells to inter-cellular spaces in tissues. These solutes act as antifreeze, allowing water in cells to remain liquid to sometimes extremely low temperatures. The above is a description of super-cooling in plants. Some plants even take advantage of another process to withstand very low temps called intra-cellular dehydration.

The roots of your plants can stay frozen for extended periods or go through multiple freeze/thaw cycles w/o damage, so long as the temperature does not fall below that required to freeze intra-cellular water. If roots remain frozen, but temperatures remain above killing lows, dessication is the primary concern. If the tree is able to take up water, but temperatures are too low for the tree to grow and make food, stored energy becomes the critical issue. Dormant and quiescent plants are still using energy from their reserves (like a drain on a battery). If those reserves are depleted before the tree can produce photosynthesizing mass (new leaves), the organism dies.

There are a number of factors that have some affect on the cold-hardiness of individual plants, some of which are length of exposure to seasonal cold, water availability (drought stressed plants are more cold tolerant), how recently planted/repotted, etc.

Al

Aha! Thanks Al. That was great. Feel free to expand the topic anytime!

You can count on him to have the definitive answer on most of these bio-cellular issues. :-)
:-) :-) Usually he makes sense, even when he's not saying what we want to hear.

xxx, Carrie

Wow- thanks, Al! I will have to read that seven more times in the hope that it will penetrate my completely non scientific brain. *no science or biology classes required in art school, ;)

I think I got the gist though, so thank you again for the thorough explanation.

When I told my husband we needed to do something about our horrendous yard and was lamenting the fact that neither of us know the first thing about gardening, he remarked, "well, it's not rocket science"....well maybe, but it IS science, and I definitely do struggle with that aspect. Any science is rocket science to my brain. Don't even ask me what I know about fertilizers, lol.

revclaus, very pretty picture! That's great that you can still have a garden when living in a high rise like that.