Forum home Problem solving

Root Barriers in Perennials Bed

Sometimes I feel like all plants are either strugglers or borderline invasive. I have small beds and keeping them balanced, without some plants overpowering others is hard.
I don't mind plants that form a clump which slowly gets bigger, these are perfectly fine and I can divide them every 2-3 years as needed. My problem is with plants that send runners/underground roots and grow a new plant 20-30cm far from the mother plant.
Have you ever try or would you consider using a root barrier in perennial beds? Maybe something as simple as a flexible piece of metal or plastic placed around the plant or to divide the bed in compartments. Or using a buried bottomless pot. I use a buried pot for mint in my herbs bed (with a bottom but the roots grow through the drainage holes anyway, so I think bottom or no bottom doesn't matter too much) and the idea of using a similar solution for some perennials sounds good to me. I could lift the pot and divide/thin the plant as needed, without disturbing plants or bulbs around. What do you think?


  • Pete.8Pete.8 Posts: 11,298
    I have a patch of raspberries in a raised bed and wanted to stop the suckers escaping so I got this

    4 years later and the raspberries have not escaped.
    I left a couple of inches of it above the soil surface so I can still mulch around the raspberries

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • Bee witchedBee witched Posts: 1,295
    Hi @edhelka,

    I've done this will Lysimachia ciliata 'Firecracker' .... it's a lovely plant but a well known escape artiste!

    I've used some wide damp proof membrane we had left over when we built our house.
    Five years on and it's worked a treat.

    I've also used a very large, bottomless pot to keep 
    Sorbaria sorbifolia 'Sem' in check.
    I dig round the edge of the pot a couple of times a year to sever any runners, they are easy enough to pull out.

    Bee x

    Gardener and beekeeper in beautiful Scottish Borders  

    A single bee creates just one twelfth of a teaspoon of honey in her lifetime
  • LynLyn Posts: 23,190
    Ive used plastic compost sacks to keep out a patch of ground elder I haven’t got round to digging out yet.
    Gardening on the wild, windy west side of Dartmoor. 

  • LoxleyLoxley Posts: 5,689
    I guess if you use weed membrane you can have a barrier to all sides and underneath, and there's going to be better moisture exchange and drainage with the surrounding soil.
    "What is hateful to you, do not do to your neighbour". 
  • LynLyn Posts: 23,190
    I isn’t  underneath, just straight down, chop down with a spade and insert the cut up bag. 
    Gardening on the wild, windy west side of Dartmoor. 

  • edhelkaedhelka Posts: 2,350
    Thank you for the comments, some good ideas here.
  • Lizzie27Lizzie27 Posts: 12,401
    I share your pain @edhelka. I too prefer nice tidy clumps to perennials that run underground and I do wish the books/online research would make it easier to distinguish between the two.  It is sometimes mentioned that a plant is invasive but not all are noted. I find the descriptions of hardy geraniums are amongst the worst. 
    North East Somerset - Clay soil over limestone
  • edhelkaedhelka Posts: 2,350
    It's quite understandable that sellers don't want to mention that but I agree it would be helpful.
    My nemesis at the moment are hesperanthas, I love them because they are evergreen here and autumn flowers are lovely but they behave similarly to crocosmias, creating underground rhizomes and small plants with tiny bulbs at their ends, often running quite far. In spring, I uprooted one clump and tossed it in an empty pot (with no added soil!) next to my shed and it's still there, half a year later, alive and flowering.
    I was also surprised by monardas. I was warned in the Garden Gallery that they can die in winter and maybe they will, but for now, they sent underground runners in all directions from the mother plants.
Sign In or Register to comment.