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gonzyro

Root pruning

gonzyro
18 years ago

Hello! I need some info about root pruning. I read that if the plant is too packed in a pot, you can prune the roots and repot it with new soil. Is this good for the plant? What part of the roots should I prune (top, sides)? How much can I prune?

Thank you!

Comments (13)

  • username_5
    18 years ago

    Well, it can vary, but as a general rule you root prune to contain a plant's size. Bonzai would be the extreme example of this.

    If you want your plant to grow larger then you need a larger pot.

    Which roots do you prune? In most cases all of them that extend beyond the limit you wish them to be. An exception would be the oddball plant with a taproot such as some trees. I don't know what is done in this case.

    Often if you prune roots you need to prune the above ground portion of the plant as well. Not all plants respond well to this. The issue is that plants take up water via roots and lose water via leaves. If you reduce the amount of roots then you reduce the plant's water uptake ability while leaving the rate the leaves lose water the same. Placing your newly root pruned plant in an area out of direct sun is a good idea for a few days while you see how it responds.

  • tapla (mid-Michigan, USDA z5b-6a)
    18 years ago

    Temperate plant root-pruning/repots are best undertaken while plants are post-dormant and just before buds move in spring. It's difficult to give advice across the board w/o knowing the material you're inquiring about. Deciduous material generally tolerates removing all soil from roots very well, while conifers accept the treatment with varying degrees of resentment.

    The largest of roots serve no function other than to anchor the plant and prevent it from toppling when it is planted in the ground. These roots are useless in container culture and are always to be removed first. The fine feeder roots are the most valuable & are what you should retain.

    The recommendation to remove top growth commensurate with rootage removed is passé. This practice should only be adhered to when repotting while plants are actively growing, a practice that is risky, even for those with plenty of repotting/root-pruning experience and is best attempted in situations where the only choice is repot or lose the plant.

    The practice of root-pruning/repotting is not only good for the plant, but is the only practical way of addressing the desire to keep a plant from declining after several years of simply "potting up". If you do not remove the largest roots so fine feeder roots can regenerate, the large roots will soon occupy a large % of container volume at the expense of valuable room for fine roots. There are other physiological reasons causing plant decline when large roots grow in congested proximity to each other as well.

    If you wish specific recommendations, you'll need to provide the type of plant material prompting your inquiry. Root work on tropical and sub-tropical plants is generally best undertaken at the beginning of the month in which the plants exhibit the most vigorous growth - that would be mid-Jun to mid-Jul in your zone.

    Al

  • gonzyro
    Original Author
    18 years ago

    Thank you both for your answers....They are very helpful. For more detail, I´m refering to a new Pothos that I have, which I repotted when it came home, but the new pot is only slightly larger than the old one. I took some of the old, dry soil the plant had between the roots, and replace it with some new soil. It didn´t fit too much of new soil, so I´m not sure if it will have a lot of nutrients.
    I don´t want it to be much larger, because I want it to be bushy and later propagate it. This plant will stay indoors, since I can´t have it outdoors (and besides I already lost some plants to squirrels/bugs/weather).

  • username_5
    18 years ago

    Since we are talking about an indoor plant forget about pruning the above ground portion, it isn't necessary.

    Since we are talking about pothos, forget about how to root prune, it doesn't really matter as they are a very easy to propogate plant and don't really require roots, they readily regrow whatever they need and aren't easily set back by over zealous pruning of any kind. That is why they are so easy to propogate from cuttings.

    Very hardy plants. Pothos is grown in soil, soiless mixes and even in fish aquariums. Do as you wish with it.

    About all you can do to harm it is expose it to direct sun, or drastically under or over water it. Sounds funny to say you can overwater a plant that will grow in aerated water, but in soil you can.

  • rhizo_1 (North AL) zone 7
    18 years ago

    Username, pruning the above ground portions of an in-ground plant to compensate for root loss is counter productive, to say the least. Passe' for certain! The leaves are the plant organs responsible for making new roots! If you reduce those little factories, you place your plant in serious jeopardy. Even field grown trees and shrubs are no longer top pruned when they are dug from the field, though as much as 90% of the root system is likely left in the ground. Root regeneration occurs rapidly, but not when the top is pruned.

    Gonzyro, as Al said, root pruning can be hugely benefical for our containerized plants. Your pothos will benefit greatly by some careful and thoughtful root removal. Though they are easy plants to propagate, they certainly can't survive without a root system, so be conservative. I prefer to use sharp shears for root pruning so that I severe the roots rather than smash them. New 'fine roots' will form as a result, giving your plants a new lease on life.

  • username_5
    18 years ago

    Rhizo,

    If that is the case then why are cuttings usually stripped of all but a couple leaves before being placed in a rooting medium?

  • username_5
    18 years ago

    Rhizo and tapla,

    I want to make sure we are on the same page here and not talking past each other. Rhizo you mentioned 'in ground plants', but the OP mentioned a plant in a pot.

    Al, you said top pruning shouldn't be done unless the plant is root pruned while actively growing. Given that the OP is asking about root pruning now, the plant would be actively growing.

    I did say, after finding out the plant in question was an indoor grown pothos that top pruning wasn't necessary, but I simply do not agree that top pruning along with root pruning is "passe". It is a common, successful cultural practice with many plants and has been for a long time.

    Also, while the leaves are 'energy factories' they are also water transpirers. The energy from the leaves is stored inside the plant. The idea is that the plant has enough energy to regrow the roots, but can dehydrate if transpiration isn't reduced. This can be done via pruning in the dormant season, removing the plant from sunlight, reducing the green leafy portion or a combination of the above.

    Nobody is talking about trees and shrubs which may well be a completely different story given that many of these do not regrow roots as readily as non woody plants nor do they dehydrate as rapidly.

  • tapla (mid-Michigan, USDA z5b-6a)
    18 years ago

    I'm not sure what you wish me to reply to. You address Dorie and me, and then go on to tell me what I said before disagreeing further with Dorie, who you'll find well-equipped to discuss the nuances of root (re)generation in plant material, if she chooses.

    Perhaps rereading my post and noting that the first two words of my post were "Temperate plant ...", will eliminate your quarrel with what I set down. A little research will show what I suggested is practiced in nearly all nursery operations and well incorporated into current horticultural thinking. That a particular practice is "common" and has been used for ages, doesn't mean it's the best way to treat plant material. I'm not talking about root/top pruning now, but habits in general. "Successful" is a subjective word. To the lions share of growers, "successful" simply means the plant tolerated it, while to others, success means something different - "a predictable plant response that results in improved vitality or achieves a planned end" is more along the lines of what I'd need to see to consider what I did as successful.

    Al

  • username_5
    18 years ago

    Thank you for your response. I was bothered by your refering to my suggestion as 'passe' and counter productive. I wanted to see if you could substantiate the claim.

    It appears that unless you put all sorts of qualifiers on your assertion you can't. That is all I wanted to know.

    I don't wish to quarrel or debate on this site, that isn't what I am here for, but if you are going to use insulting terms directed toward me or what I say you will find I am not real inclined to accept it. Goodness knows I learn a lot here and have been wrong before, and will be in the future, but I don't take kindly to put downs.

    I have read many of your posts and consider you very knowledgable and helpful.

    Enough said.

  • tapla (mid-Michigan, USDA z5b-6a)
    18 years ago

    There is a stark difference between pre-qualifying a statement, which is what I did at the very beginning so it was clear I was speaking of temperate plant material and adding qualifiers after the fact - you'll find I never do that and I don't waffle. Near the end of my post, I also made it clear I had switched from temperate to tropical or subtropical plants so there could be no misunderstanding.

    Everything I said is true, including the fact that current thinking advises that when transplanting/repotting temperate plants, it is best to leave tops unpruned.

    You're too quick to assert that I'm unable to substantiate any post I might leave on these forums. If you feel the need for me to explain the principle, I can certainly do that - it's simple botany and I had adhered to the practice long before it became contemporary. I'm not sure what purpose it would serve though, as it was revealed subsequent to both our original posts that the subject plant material is a tropical vine.

    Al

  • gonzyro
    Original Author
    18 years ago

    Well...I´m sorry my post produced such discussion. I just wanted to thank all of you for your help and advices. I´ll read carefully all that you wrote, since it´s a little too advanced for me and my plant knowledge.
    Thanks again!

  • rhizo_1 (North AL) zone 7
    18 years ago

    LOL...gonzyro! Sometimes this happens; we just CAN'T help ourselves! Here's what I would do if I were thinking about my very first root pruning attempt!

    First, don't be afraid. It's a GOOD thing! People have been doing it to all kinds of plants, all over the world, for thousands of years. Be conservative and there is no chance of doing your plant any harm, or causing any kind of stress.

    Take your sharp scissors or shears and simply cut away a couple of inches from the bottom of the root mass. For your first 'operation', that won't be too scary. You can pull the roots down a little to separate them. When repotting, just put some fresh soil in the bottom to compensate for the loss of root volume.

    When I root prune a plant, I detangle as much of the root system as possible and give a conservative all over 'haircut'. If the root mass is highly fibruous and entertwined, then I simply take a sharp knife and remove small slices from the sides and the bottom.

    If your plant has been root bound for quite some time, then be prepared for a spurt in top growth in a short time. As a rejuvenated 'absorbing' root system is quickly formed, your plant will suddenly be able to take up more water and solutes than it has been able to in a long time.

    Good luck, have fun,....and 'don't be afraid'!

  • gonzyro
    Original Author
    18 years ago

    I will try not to be afraid! THANKS!

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