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Compacted clay in an established rose bed

I'm hoping some one can help please: I am trying to recover an established rose bed in rock solid compacted clay (my poor back)! I understand gypsum helps to break up the clay but will it have have adverse effect on the roses? There are also Cranesbill geraniums and a hydrangea in the bed.

Thank you in advance for you help.



  • I'd steer clear of the gypsum idea. Heavy clay soil (which is predominant around here) is tough going when set like concrete or saturated and sticks to everything.

    To create a better soil consistency, give it a good soaking (don't go OTT) to make it easier to dig, then dig in plenty i.e. lots of organic material.  Well-rotted manure is ideal, compost or even chicken manure pellets will make a difference. 

    Clay soil particles are incredibly small and decreasing the particle density will make the soil much easier to work with and far more fertile. The worms will also love the new material and further increase the quality of the soil.

  • CloggieCloggie Posts: 1,457

    So, is the idea that the roses will do better than they are now?  I thought roses liked clay.

    If it were me, I'd spend a few years throwing manure and home-made compost over the top of the soil and then see how workable it is.

    I might not have the gist of what you're trying to achieve though so shout up if I've misunderstood.

  • raisingirlraisingirl Posts: 7,009

    I'd go with Cloggie's plan. Thick (at least 2 inches) mulch over the surface, don't attempt to dig it in. Gypsum is not terribly effective - frost and worms do more and faster. So feed the worms, let it be over winter. See what it's like in the spring. You may need to mulch again then. or you may find you can get a bit of purchase (especially if we have a cold winter). Be wary of thick manure around the hydrangea, maybe use bark chips there instead. The geraniums will be fine.

    In future years mulch every spring rather than in the autumn so the frost can get at the soil surface over winter. You'll find it softens up in time but there is no quick fix.

    “It's still magic even if you know how it's done.” 
  • LbirdLbird Posts: 3
    Cloggie says:

    So, is the idea that the roses will do better than they are now?  I thought roses liked clay.

    If it were me, I'd spend a few years throwing manure and home-made compost over the top of the soil and then see how workable it is.

    I might not have the gist of what you're trying to achieve though so shout up if I've misunderstood.

    See original post

     Well, the initial idea is to remove the weeds and grass that are growing through the bed after who- knows-how-long of neglect. The immediate aim is to make the soil easier to work: it is like iron at the moment and after 3 hours of digging today my back is killing me and there is very little progress. My plan was to chuck bags of organic manure on it which I hoped would make the soil easier to work and benefit the (currently rather poor) roses. From Dave Hedgehog's reply and yours, it seems as though this isn't a bad idea :-)  Thank you both for your input :-)

  • CloggieCloggie Posts: 1,457

    It will be like iron at this time of year, Dave H mentioned watering it down but I'd still be tempted to smother the weeds with top dressing as an easy fix.  

    If it's been neglected for a loooong, long time then it could be that the original planter was old school and manured it each spring so the plants might have had a great start in life?

    Take pictures now and later after you've g'eed it up so you can keep track of progress.  Any that don't respond, you might want to bin in a couple of years but that job will be easier if you improve the soil.  Roses have surprised me as being really tough plants and have a deep, tough taproot.

    Best of luck, we'd love to see photos of now and progress.

  • The weeds need to come out and if the grass is couch grass, all its Christmases will come at once. 

    It punches straight through most weed membranes and a mulch will be no issue at all and make it grow with extra vigour.

    By all means, spread a mulch or plenty of manure, compost on top and the worms will take care of the digging aspect when the soil is't rock hard.. But couch grass and certain weeds will intertwine with rose roots and suppress their productivity, not to mention being a nightmare to get rid of without a chemical warfare approach.

    Last edited: 07 August 2017 19:59:46

  • ObelixxObelixx Posts: 29,843

    I don't think I'd try and dig it now but Dave H is right about removing pernicious and persistent weeds so, if it hasn't rained, water as advised and then just fork out the main weeds and leave them in a pile to dry thoroughly before they go anywhere near a compost heap.

    Rather than dig the whole bed, push a good strong garden fork in as deep as you can and wiggle it about to expand the holes.   The holes will provide much needed air to the roots and also allow rain to penetrate deeper.   Then mulch between roses and plants you want to keep with a couple of inches of well rotted manure or garden compost or bought compost mixed with some fine grit if you can get it.

    Come autumn, mulch again when the perennials have died back and then leave it for the worms to work away.   However, if you do decide to dig, autumn is the best time just to loosen the soil clods with a fork and then leave them to the frosts and mulch, as above, in early spring.

    It may take a few years to get it looking and feeling like really good soil if the soil is really compacted but you should see an improvement in plant growth and health by next spring and every passing year.

    Vendée - 20kms from Atlantic coast.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • I know no one likes to talk about it but couch grass snuffs it really well with the gel glyphosate directly applied to it...

  • B3B3 Posts: 27,007

    I'd whack the soil with the pointy end of a slater' s hammer or similar to loosen the soil a bit before you add the compost or manure.

    In London. Keen but lazy.
  • LbirdLbird Posts: 3

    Thank you all for such great replies!

    The soil IS like iron at the moment, hence my original post :-) I am, nonetheless, getting the weeds out. To my surprise and relief, the thistles were relatively easy. The rosebay willow herb is, on the other hand, proving a real bugger (fortunately I've found no couch grass yet). I'm doing this as a one-off job for someone so on-going care is unlikely, unfortunately. Still, if I can at least get one 'major mulch' session done, it may help the next person who comes along to do the rescue and repair (who knows, it may be me)!

    imageBed 1 BeforeimageBed 1 AfterimageBed 2 BeforeimageBed 2 AfterimageBed 3 Before imageBed 3 After imageBed 4 - about to start!

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