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Is it mad to take a plant out of a pot and thin out the roots?

Mrs_MigginsMrs_Miggins Posts: 60
in Plants
I've lots of things in pots and they keep growing. There's not much ground (borders all full or not enough sun) and I'm wondering whether some plants would be ok with being lifted out, having the roots trimmed and put back with fresh soil? 
Or with some whether I can get away with trimming roots vertically from the top (prob won't come out of pot). 
Plants I'm thinking of are
hebe
hardy jasmine (40cm sq pot)
common jasmine
climbing rose ( gulp. I know. 40cm square pot)
geum
hydrangea
sarcocca
choisa ternata
clematis
standard bay trees. 

the rose really has nowhere else to go and the only other thing I could do would be to lift up a paving slab 80cm x 60cm and dig it into the ground which is right near the house. But that could be tricky and would it cause problems having open ground backing onto the house? 

I have a spot for the hardy jasmine but it needs prepping and it won't come out of the pot. Its roots are solid. Help!! 

Posts

  • PlantmindedPlantminded Posts: 3,580
    edited October 2021
    Hi there, root pruning is often helpful when plants become pot bound.  I did it last year to two 20 year old box balls, quite dramatically, and they seemed fine afterwards and have continued to thrive.  (I had upsized the pots in previous years a couple of times.) I'm not sure how all the plants on your list would take this though - other forum members with experience will no doubt advise you.  There's a helpful GW article and video on this subject:

    How to Root-Prune Pot-Grown Trees and Bonsai Trees - BBC Gardeners' World Magazine (gardenersworld.com)

    I would only refresh compost on the top of any pots at the moment and leave any root pruning/division until the Spring.  Whatever you do, remember that the upper part of your plant will only thrive if the roots are happy!  
    Wirral. Sandy, free draining soil.


  • JennyJJennyJ Posts: 10,576
    For getting a root-bound plant out of its pot, a couple of things that sometimes help are a really good soaking (plunge the pot into a larger container of water and hold it under the surface until bubbles stop coming up and it stops trying to float), and sawing down around the inside of the pot with something long like an old breadknife. And a helper to pull on the pot while you hold the plant, if it's got a strong woody stem.
    Doncaster, South Yorkshire. Soil type: sandy, well-drained
  • Mrs_MigginsMrs_Miggins Posts: 60
    The rose and jasmine pots have an overhanging lip of about 2 cm all around. The jasmine will be ok I'm sure, but I'm more nervous about the rose. 
    I'm going to watch that video and see if it is possible to do any of it soon as some might not flower if I do it in spring. (Choysia is quite early I think). 
  • Doghouse RileyDoghouse Riley Posts: 347
    edited October 2021
    Earlierr this year, I thinned out the roots of the six hebes we have in pots in two troughs  on the patio. I knew it needed doing as it was very difficult to push a cane into the soil in any of them. I've done it  a couple of times over a few years

    We've a sambucus and a mimosa in really big pots, we've had them for years. They are too big to pull them out to check the roots. But a couple of times a year I push a thick cane down through the soil in several places about six inches in from the rim, this allows water to get to the roots rather than running down between the sides of the tubs and the root ball. They both do very well every year.
  • FairygirlFairygirl Posts: 55,117
    You'd really need to remove them and root prune properly, as @JennyJ and @Plantminded describe. Nothing else is likely to work. 
    Some of those may not respond well either. Many Hebes can turn up their toes if treated too harshly, unless you have milder, more suitable conditions - same if you prune the tops too hard. 
    Geums just get divided, and spring is better for that. Most perennials need divided every few years to keep them thriving. Some geums are shorter lived too, unless they have the right conditions. 
    Clematis need proper care, and if you don't have the room in the pots they're in, then you need a bigger pot. If they're young enough, you can divide them, but it also depends on the type you have. 
    Choisyas might be ok being root pruned, but it's not a shrub I'd ever keep long term in a pot. Same with Sarcococca.

    I don't grow jasmine as it doesn't survive here, but it would probably be in the same category as clematis, and the rose would possibly not be happy either. I don't really like roses, so I no longer grow them, but I wouldn't have put climbers in pots. If you can, definitely put that in the ground, after improving the soil really thoroughly. Mine were right next to the house, along with clematis.  :)
    Bay trees don't survive outdoors here, other than for summer, but again, you may need to be very careful what you do with them. Someone else who grows them might be able to advise on that. I think @Dovefromabove has some    :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
  • Mrs_MigginsMrs_Miggins Posts: 60
    Well I repotted my hebes a couple of years ago and getting one in particular out of its pot was a massive struggle. It lost loads of roots (the pot had a ridge inside). That one took a year to recover! I don't want to lose all of summers flowers. But these pots are much easier. So I think a gentle trim now so nutrients and water can get down and some fresh soil will do for those. 
    Like the idea of the canes, that could buy some time for the rose and jasmine. 
    The house is a Victorian terrace in London and god knows what's under the paving. Years of crap I should think!
  • FairygirlFairygirl Posts: 55,117
    It might be worth taking cuttings of your Hebes @Mrs_Miggins. They take quite readily, although this isn't the best time of year really. Try it in spring. I did that with one of mine, because although many of them are great in pots, they don't always make it through harder winters here, and even if they survive, but have some dead areas, and cut them back, they don't always come back from that. I've got one in the front garden which is only half a shrub because it was badly affected a few years ago.
    I have a self seeded one which is much sturdier, but it's when they're potted they're much more vulnerable. It probably won't be as cold and wet where you are though, and it's when it's wet then a freeze, it can see them off.  :)
    It's a place where beautiful isn't enough of a word....



    I live in west central Scotland - not where that photo is...
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