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christinmk

Container gardening for the perennial lover

Yes I know there is likely some forum especially for this subject on GW.

I'm curious to know how many of you garden in containers and what your experiences have been. What have you grown in them? What has worked and what hasn't? What is your favorite type of pot? Your method of overwintering both plant and pot? Favorite soil/mix to use? How frequently do you find you need to change the soil? How often do you feed your potted perennials? How often do you tend to divide or root prune (on shrubs/trees)?

I must say the idea of getting into gardening in containers is a tempting one for me. My favorite plants are shady ones, especially the delicate unusual ones. Problem is, there is literally no space for them in any garden beds. I DO however have shady spots where pots will work. Its something I'm considering anyway.

This is my second year growing my ornamental rhubarb in the half whiskey barrel. It is doing MUCH better than in the ground, which was a lot dryer and hotter. Its looking a bit rough now, but I'm not sure that isn't just the nature of Rheum. I'm very curious to see how it does next year and whether or not it declines. I'm not looking forward to popping that big guy out of the barrel and repotting it at all, LOL.

Anyhoo, I would love to hear what your experiences have been with growing perennials long-term in containers.
CMK

Comments (20)

  • gardengal48 (PNW Z8/9)
    10 years ago

    christen, since I moved and downsized, I garden almost entirely in containers. I do have some garden space but it is on the most amazingly steep slope, so I save that area for my cast iron growers or those that simply get too big for containers so I don't need to assume my mountain goat persona too often :-)

    I grow just about anything in containers - my collection of dwarf conifers, Japanese maples, any sort of "cool" plant that comes across my path at the nursery, fruits and vegetables, sedums and succulents, clematis, and mixed plantings of perennials, grasses, small shrubs, annual color, groundcovers, etc. Sometimes I do mixed containers, sometimes I devote a single plant (more so with my trees). All - except for the tender succulents - live outdoors year round. No special care, no winter protection. Obviously that laissez faire attitude will not work everywhere :-)

    Since most of my plantings are semi-permanent, I use a very high quality, durable potting soil that lasts at least 3-4 seasons......no MiracleGro!! Something very close to Al's 5-1-1 mix from the Container Gardening forum (excellent resource btw if you are contemplating pursuing this in depth). I use Osmocote when I pot up and again at the beginning of the new gardening season and now and again a little dilute liquid fertilizer through the summer, depending on the plant.

    I splurge on containers - I buy frost proof glazed ceramic pots but get a nice employee discount from the nursery and can buy wholesale from a couple of local suppliers. I tend to focus on a single color range for containers (kind of a mellow, streaky green called "frog spawn") which seems to blend into the background so all the plants stand out. I do have a few reds as accent. And I use terra cotta almost exclusively for the succulents. Over the years, I have assembled a nice collection of containers, but I'd hate to think of what they might have cost if I had to pay full retail and all at once!

  • christinmk z5b eastern WA
    Original Author
    10 years ago

    Great info on your container gardening Pam. Your dwarf conifer collection sounds awesome. I'd ask to see a pic, but seem to recall you don't have a camera? ;0) I keep shooting myself for not snagging the mini 'Whipcord' Thuja we got at the nursery awhile back- it would have been perfect for a container.

    Thanks for the reminder about that soil mix- I remember reading about it before but it had slipped my mind. Is it pretty good draining then? There is always a few days in early, early spring here where the ground is still frozen and we get some rain that just seems to pool up. That has always been one of my main holdups to doing more container plantings I suppose- wondering about the drainage. That and whether or not mulching them for winter is necessary for some of them (yeah, a laziness thing here too, LOL).

    I had to laugh at the "frog spawn" comment. It is hilarious the things they name the colors of the pots. We have a couple at work, like "Wasabi" (a polite name for the color imo) and "Ox-Blood". I ought to get the red one and tell people I'm growing my plants in Ox blood ;-D Lol.
    CMK

  • katob Z6ish, NE Pa
    10 years ago

    I usually save the containers for annuals, it's easier for me to water and keep an eye on them that way, but there are usually a few perennials sneaking in here and there.
    Hostas sometimes show up on the front porch, other new perennials occasionally spend some time on the deck (so I don't have to keep going outside to admire them again and again!)
    My favorite plantings were three large pots of miscanthus out on the deck. Last winter was too much for them and I tried something new this year, but I miss them, and you can bet they'll return next year.
    I'm also building up quite a collection of terracotta and succulents... not the smartest habit come fall and the first frosts.

  • woodyoak zone 5 southern Ont., Canada
    10 years ago

    I've been reducing the use of containers as I find watering them a PITA. I only grow perennials in a few of them, and just for a year at most before planting them in the ground. Hostas overwinter easily in the garage and giving them two summers in the pots makes for nice big plants when they go in the ground at the end of the second summer. The heucheras planted in pots this summer will go in the ground this fall. Next spring I want to try edible rhubarb in a pot to see how that does since I love rhubarb but have no appropriate place for it in the ground.

  • christinmk z5b eastern WA
    Original Author
    10 years ago

    -Kato, LOL!! I have made the mistake of collecting large terra cotta pots too. After a couple years lugging them inside I rather regretted not getting frost proof pots instead! :-P

    -woody, couldn't you have left the hosta pots outside during winter?? Or was it not a winter hardy pot?
    CMK

  • katob Z6ish, NE Pa
    10 years ago

    Woody- I set up all my pots with drip irrigation this summer.... AWESOME! We went away for 10 days during a heat wave and everything was lush when we returned. Still waiting for the water bill. It shouldn't be too bad, but the timer broke and stayed on for all of those 10 days.... good thing I use a potting mix with decent drainage.

    Christin- I think I still have about three more years before I learn my lesson. Right now I'm only just figuring out not to plop down terracotta pots too abruptly. Two brand new pots out of the trunk and onto the garage floor.... you do it a little too fast and you're looking at $30 worth of clay shards (which btw you can't return).

  • prairiemoon2 z6b MA
    10 years ago

    Gardengal48, I didnâÂÂt know you were gardening in containers now. I thought you had a large garden, but was that in your old house? Are you missing it?

    I hadnâÂÂt thought about how much easier it would be to do containers in your zone. That is great that you donâÂÂt have to drag everything in the house every fall, or worry about pots freezing and cracking.

    IâÂÂm very interested in what you use for soil. IâÂÂve attempted to mix my own and have read AlâÂÂs threads on his 5-1-1 mix, but I havenâÂÂt been able to find the main ingredients locally for it. Are you mixing your own, or buying a brand that is close to his mix? And your fertilizer, I usually use the Espoma products and wonder if that is about the same as Osmocote. And I use Fish Emulsion/Seaweed liquid during the growing season.

    I used to pot up about 20 containers a summer, but I found the whole routine too much of a project every year, not only getting them all ready in the spring, but dragging a lot of them back in the house for the winter. And like Woody, I find keeping them all watered a daily chore I find hard to keep up with. Now I have less than 5 every season.

    I think it makes a difference whether you are still building your garden or not. I have a lot of work still left to do in the garden. Projects waiting for me every spring and fall, so the work of containers just takes my time away from those. If your garden is established and you are running out of room, I think containers would be great for expanding your options.

    I do have two pots that are freeze proof that I leave outdoors all season. IâÂÂve had them in place for 5 years now. The plants had to be hardy two zones more than here, so zone 3 and 4 plants can stay out there all winter without a problem. I planted Arborvitae and Sedum angelina for a year round accent because my property is so flat. They really need repotting, which IâÂÂm not looking forward to it. We really enjoy those two containers, they are part of the landscape at this point. We moved them temporarily out of their usual spot this spring and we really missed them.

    Kato, I would have to try that drip irrigation system if I were going to try a lot of containers again. Which system did you use?

  • woodyoak zone 5 southern Ont., Canada
    10 years ago

    CMK - the pots all need to go in the garage for the winter to clear the driveway for snow removal. Plus the pots the hostas were in were not very big so they wouldn't have offered much protection for the hostas if they were left outdoors.

    I can't figure out how to set up a drip irrigation system for the driveway pots without causing a trip hazard from a hose running to them! So hand-watering with the hose or watering cans is the only option. As the years pass, that has become a less desirable chore so each year there is fewer pots out there....

  • jadeite
    10 years ago

    Dumb question - are all glazed ceramic pots frost-proof? I've never used them outdoors through a winter when I lived in Z5 and 6, but now I'm on the border of Z7 I'm wondering how risky it would be. I'm not dragging huge ceramic pots loaded with soil and plants indoors, it's not worth the back pain. I have some container plants in light plastic pots which are on a wheeled shelf which are moved outdoors in summer and back inside when frost is likely.

    Thanks,
    Cheryl

  • mxk3 z5b_MI
    10 years ago

    I do have a mature Rodgersia in a very large half wine barrel. I potted up last year, I don't think I get a pot any bigger - ?. Obviously, he stays out for the winter, no way no how can he be moved for storage, there are steps to that patio and DH and I can barely push him let alone lift him. So, we just push him against the house for the winter and barricade with bags of leaves until spring - he's done fabulously all these years. I also have a small hosta which Ken gave me that is happily growing in a pot, but he really should be planted in the ground (the hosta, not Ken LOL!)

    It's do-able, but I'm really not a fan of growing perennials or shrubs in pots - I don't think they reach their full potential in pots, and if you get into really large, heavy pots they're difficult to deal with (as above). I was growing a butterfly bush in a pot, but recently I realized the potted one was not as large nor floriferous as the ones in the ground, although admittedly she did flower earlier; she's being planted in the ground this fall. I'm with above poster - would rather plant annuals in pots.

    That being said, I have grown roses, tree peonies, butterfly bushes, etc in pots until I was ready to plant them, or they matured to the point I felt they were ready for planting, and I still have a alba rose in a pot because I don't know what to do with her yet I want to keep her - but again, not at her full potential, as she's limited by the size of the pot.

    If you want to overwinter shrubs or perennials in colder zones, you have to winter protect in some manner. As I mentioned, I push Rodger against the house, but the other stuff is dragged into the garage for the winter for storage and taken out in the spring. I've posted re: my winter storage method in the past, just do a board search and you should find old post(s) about it (watering, taking out in spring, etc).

    I do not keep my ceramic pots outside in the winter. I plant in plastic pots that are slipped inside of ceramic pots; ceramics pots are stored in the crawl space for winter. I've got some beauties, not worth the risk of frost/ice damage.

  • mxk3 z5b_MI
    10 years ago

    And yea, watering is indeed a PITA, as woody already mentioned. Anyone who's been around here long enough knows I HATE watering anything, so the less of that I have to do the better. I grumble about it but still grow annuals in pots, they do brighten up the patios and I enjoy them.

  • gardengal48 (PNW Z8/9)
    10 years ago

    CMK - I use a purchased mix but it is very close in composition to Al's mixes. And I actually use a slightly different but much more barky mix for my trees, very similar to what many growing nurseries use for their container mixes. It holds up really well (even longer than the 5-1-1) and is slightly acidified, which is ideal for most trees and conifers, especially the Japanese maples.

    And I do have a camera on my phone but it is a stupid (as opposed to smart!) phone and I can only email them AFAIK. I am technically challenged at the best of times and as I do not have Internet at my house, I am reluctant to mess with my work computer for that......:-( But I'll see what I can manage going forward.

    prairiemoon - Yes, I sold that place and moved to never-never-land - a cottage on the beach (Puget Sound) with incredible views. Do I miss the old place? Not at all, although I do miss some of my plants, mostly the trees. It was a very complex garden with way too many plants and became much more work than I was inclined or able to manage. The containers are just enough now although I seem to keeping acquiring more plants and therefore more containers. It's an unshakable addiction!!

    One thing about fertilizing containers - since they contain no real "soil" (potting soil = soil-less mix) and minimal organic matter, they seldom support populations of soil organisms necessary to assimilate dry organic fertilizers......like Espoma products. Water soluble or liquid organics (like fish emulsion, seaweed, even compost tea) or any other water soluble fertilizer (Osmocote, MiracleGro) works much more efficiently. For a liquid fertilizer I use a product called Liquid Grow from Dyna Gro that contains a lot of trace elements necessary for good plant growth that many other fertilizers lack. With long-term container plantings the three things that must be dealt with carefully are the quality of the potting medium, fertilization (they rely on the gardener for everything) and proper watering.

    Because good drainage is so critical in containers, I find I can grow more marginal plants more easily. Although it can sometimes get pretty darn cold here in winter, it is not typical but a lot of wet is. And plants that often do not care for our winter rains in the ground seem to do just fine in a well drained container.

  • prairiemoon2 z6b MA
    10 years ago

    Gardengal, never-never-land is right! A cottage on Puget Sound would make gardening in containers totally worth it. :-) I can only imagine what scenery you have to look at. Natural beauty like that can easily take the place of a home garden.

    Yes, I do understand that the organic fertilizers need the soil organisms to work and that potting soils are soil less. Sterilized as well, right? It leaves me in a dilemma, because I donâÂÂt even want to purchase inorganic products. Especially if attempting to grow food in containers. I am happy to use Seaweed/Fish Emulsion, so IâÂÂll just leave out the Espoma, since it seems to be a waste of money in containers.

    IâÂÂve tried making my own potting soil mix, with peat, perlite and small amounts of bagged Coast of Maine compost, but I am not getting good results with it. IâÂÂm wondering about increasing the amount of compost, or adding a small amount of actual soil from the garden to the mix. The only other thing I can do is purchase organic potting soil mix. The bark mulch fines in AlâÂÂs recipe was one of the ingredients I couldnâÂÂt find locally to add to that mix. I donâÂÂt think I am having any trouble with drainage though. I think it is a case of not enough nutrition.

    Well, thanks for sharing your methods for container growing and good luck in your new house!

  • katob Z6ish, NE Pa
    10 years ago

    Waaaaa. I want a waterview cottage too!
    Good job gardengal, it sounds like a perfect spot to really enjoy.
    I never knew that about the dry organics, thanks for that info.

    pm2 - I ordered the parts from dripworks, I believe they have kits you can buy too.
    The costs can add up there so if you're interested in just experimenting with a starter set, click the link for a real low cost harbor freight version. $6.99, how can you beat that? I would buy two at that price and add parts as you get a better idea of what you want.

    Here is a link that might be useful: starter kit

  • river_crossroads z8b Central Louisiana
    10 years ago

    What, no pictures? I made up a folder of some of mine, see below. At my house I specialize in easy-care perennials so these are all easy-peasy. I had to experiment with different light to get them to bloom but that was easy, too. Nothing special here in 8b, heat zone 9.

    Gardengal, is your fave potting mix a national brand? If so could you tell me what it is? I can request âÂÂship to storeâ at Ace Hardware and some other places. Otherwise of course shipping cost is prohibitive. IâÂÂve read of AlâÂÂs mix before, but too many bags to store for my small operation.

    Hey Christin, good to see you! Me, too, no space. Of course we all have different needs. For me personally it makes more sense to have plants in the ground. A few pretty perennial containers on my concrete patio are ok imho, esp since the plants are either invasive or were not getting the light that they needed.

    On the link below, you can click "Roll" above the pics and to the right of "Thumbnails" in blue, then quickly scroll through when it finishes loading - thanks for looking, anyone who does!

    Here is a link that might be useful: 4 fave perennial containers at my house

  • christinmk z5b eastern WA
    Original Author
    10 years ago

    Great info guys. Oh yeah, pics are very welcome if any of you want to share ;-)

    -River, nice to see you too!! GASP. That passion vine of yours is to-die-for. So did you end up tasting the fruit? Did it turn out to be bland or better than expected?
    CMK

  • river_crossroads z8b Central Louisiana
    10 years ago

    Thanks, Christin! The flower has just become the fruit and I need to wait until it is the color of a little orange and then gets soft. Only the one piece of fruit so far. Many buds have fallen off before becomng flowers but thatâÂÂs better now that I have it in the nice, big pot. Other flowers fall off w/o becoming fruit but I still have a lot of buds to watch. Trouble finding the right kind of pot to provide the moist but excellent drainage that is recommended. I could have drilled holes but it is easier to just buy it readymade. Was very happy to find a pot that looks right. See you!

  • gardengal48 (PNW Z8/9)
    10 years ago

    Sorry, slow in coming back to this.....I've been enjoying a few days off :-)

    The potting soil I use is regional rather than national. Personally, I would not trust a national brand as the ones we are most familiar with are pretty much cr*p!! If east of the Rockies, I'd investigate Farfards - if west, look at Master Nursery's Gardeners Gold or Gardner & Bloome Blue Ribbon Potting mix (same manufacturer, same product - different labels). These are pretty decent quality mixes for bagged stuff.

    Mixing your own is not unreasonable and you don't get way more soil than you need as most of the ingredients can be found in very manageable sizes. The bark fines can be some of the trickiest to locate - why, I have no idea - but there are some very close substitutes. Reptile bedding - available at places like PetCo or PetsMart - is almost the exact same product. And bark fines are often sold under the name "soil conditioners" and can be found at places like the big box home improvement stores. Just check to see that size is right before purchasing (about the size of your pinkie nail or no bigger than a dime).

    I AM spoiled by my views and location to be sure :-) But one does give up some perks for that kind of existence. One is the lack of any suitable in-ground gardening due to site restraints and the other is the extremely petite size of my cottage. But it has a huge deck - great for my container collection and allowing for any sort of entertaining at all. More than two people indoors is a crowd!!

  • prairiemoon2 z6b MA
    10 years ago

    There you are gardengal! Nice that you had a little time off while summer is still with us. Thanks for the name of the brands of potting soil. I can find Farfards locally, I'm pretty sure. Expensive, but, maybe it's worth it. I will also change what I'm looking for with the bark fines and see if that helps.

    Well, your cottage by the sea sounds very cozy. And I guess there is always a trade off, no matter what. The deck sounds wonderful and I would imagine you could just about live out there. :-) I bet all your guests don't mind staying out on the deck, one little bit. lol

  • river_crossroads z8b Central Louisiana
    10 years ago

    Gardengal, thanks so much for info on potting soil. Your huge deck with views of Puget Sound must be wonderful - sounds like it is well-deserved after lots of hard work. Enjoy!