Planting olive trees

Hi I recently cleared a 10 meter mature bamboo hedge as the roots were getting out of control and root barrier not an option  .anyway all roots are now gone and the plan is now to buy and plant 6 mature pleached  olive trees ,the problem is that the soil is thick clay with very limited drainage which isn't ideal for olive trees so Today I've cleared a trench of clay about 1.5 feet deep by about 2ft which was 2 tons that came out .I wonder if this is enough soil removed before going onto the next stage ..I was planning on getting a good draining top soil and adding in small shingle and at the bottom of the trench adding in bigger stones .would this be enough as it looks to me like the water can still build up on the remaining clay causing damage to the new trees? I was wondering about taking another 2 tons out but I will end up Having to buy much more topsoil .Its not my garden so options might be limited.the lady wants it all finished asap but is keen about olive trees .any thoughts about  please .Thanks,jack


  • NollieNollie Girona, Catalunya, Northen SpainPosts: 1,609
    Hi Jack, clearing that bamboo must have been a nightmare, hope you got every last bit of runner out, if it was the running type!

    Olive trees are grown on all sorts of soil here including heavy clay. The trick is to plant them on a slope or raised humps/berms to aid drainage. This would also help to avoid damage to the shallow root system from mowers, strimmers etc. If the area in question gets heavy rain, as you are thinking already, yes there is a possibility you have just created a big sump with the trench you have dug, for rainfall to collect. If you went for a berm arrangement, you would of course then need to consider where the excess rainfall from the berm drains to...

    A matter of personal taste, but the thought of a preached olive horrifies me, what an awful thing to do to such a magestic and naturally rounded tree, but I suppose you could say that about any pleaching.

    If the lady in question is keen on olives, couldn’t you persuade her to have a couple of nice specimens in large pots, and to choose a hedging/pleaching tree that is more suited to her ground conditions?
  • jackpjackp Posts: 20
    Hi Thanks for getting in touch ,yes the bamboo removal was a bit of a big job but it's done now and I certainly will not be taking on another job the same . As you mentioned having the trees in planters is a better option in this case but the planting area is along a fence and she is keen on having the trees the whole way along the fence line so it would have to be a very big raised planter so probably not really an option .as a next stage I have been thinking about digging in 50kg of agricultural gypsum and around 50kg of sand and 100kg of fine shingle with a few bags of organic material.Im not that sure though exactly what the plan is and if I'm doing the right thing-and if even another 2 tons should come out first before doing anything else ? the job was initially just clearing the bamboos I may even leave the rest of the job for someone else to do if there is a chance the trees won't survive if I don't get this right .and I know what you mean about preaching trees these were going to be bought as 2m clear stem trees then after 6 months we'd look at cutting the top like a hedge .
  • NollieNollie Girona, Catalunya, Northen SpainPosts: 1,609
    Hi, I was meaning persuade her to have a couple of olives in pots elsewhere (always look good framing a doorway or on a terrace) and to choose a different, more suitable tree for the 10m hedge run - e.g. both Hornbeam and Photinia pleach well, the latter being evergreen and used a lot around here, so you could sell it to her as suitably Mediterranean, if that’s her thing. Photinia grows fine in my rocky, alkaline clay, but any hedge will benefit from improving the clay.

    If she is determined to go ahead, and assuming her garden is sheltered and the trees all face south or at least get a fair bit of sun (otherwise they will likely fail anyway) I would certainly make the trench wider, 3ft minimum, as the shallow roots do spread around a lot. Ideally, then raise the soil level on top of your trench - a berm is basically a raised ridge with gently sloping sides, or make it a traditional raised bed edged with railway sleepers or similar. I wouldn’t bother with the gypsum as it’s a temporary measure at best. You can use any old stones/builders rubble to fill the bottom of the trench and then a mix of gravel, sharp sand and organic material to plant in. Maybe half gravel/sand to organic. Ideally, aim to get a total depth - filled trench + raised area - of around 3ft. Top dress with gravel, not bark or similar.

    I think all you can do is warn her that her conditions aren’t ideal, but this is what you plan to do to give her the greatest chance of success... Or, as you say, walk away.

    Hope that helps, good luck!
  • BorderlineBorderline Posts: 2,776
    edited November 2018
    Good good advice so far. You need to be mindful that the more mature a shrub gets, the harder to adapt in its new surroundings. Olive trees are not cheap, and despite following all the good steps of prep work, there is still a high chance of failure. It could be an expensive mistake.

    Either opt for smaller size plants or look at other options for more faster growing shrubs that do a similar job. 
  • jackpjackp Posts: 20
    Hi thanks for taking the time letting me know your thoughts 
    Just had the lady in question on the phone tonight the trench after a few showers has turned into a lake even though I had left it with some drainage holes obviously wasn't enough  ,I wasn't sure what to suggest just yet as the problem seems to be worse than I thought  .it seems as though it's also getting water  run off from the neighbors garden as its on the along the fence and whole area in general appears to have heavy clay with very limited drainage.I was planning on going back next week to dig out more clay and place large soak away followed by good draining soil but I'm not convinced it will be enough as the trees would be planted close the fence as well near the neighbors clay soil .I wonder if all this could just be a waste of time 
  • NollieNollie Girona, Catalunya, Northen SpainPosts: 1,609
    You can mitigate/improve/install drainage, widen and raise the planting area well above the surrounding land, provide the right, free-draining medium... but still not be guaranteed success when ultimately, as I think your instinct is telling you, olive is the wrong choice for this situation. Especially with mature plants, as borderline says, and probably also planted too close to the fence (how close is close?). You haven’t said whereabouts in the country you are or if the intended planting site is the requisite sunny, sheltered area. I think you need to sit down with the client and go through all the issues and let her decide if it’s worth the risk spending all that money with no guarantees.

    Not or sure I can add any more, but perhaps other forum members have some views or alternative advice?
  • LantanaLantana Posts: 5,557
    edited November 2018
    We used to live in the middle of an olive growing region, in fact were surrounded by the things. That location was extremely cold in winter and they withstood the cold plus the winds from the mountains. I’ve even seen them sitting in flooded fields after exceptionally prolonged or heavy rain. BUT, the soil was stony and fairly well draining. I don’t recall any area with heavy clay soil although perhaps Nollie’s experience is different?
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 52,350
    If the soil soil is likely to be waterlogged in winter olives will be very unhappy indeed. 
    I’d go for pleached hornbeam ... it doesn’t mind having wet feet in the winter. 
    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • punkdocpunkdoc Sheffield, Derbyshire border.Posts: 6,605
    As others have said, this sounds like a terrible idea, wrong conditions, and imo the wrong trees to pleach.
    Hey, shady baby, I'm hot like the prodigal son Pick a petal eenie meenie miney moe
    And, flower, you're the chosen one
  • jackpjackp Posts: 20
    Thanks everyone for your thoughts about this .
    So I've now come to the conclusion that olive trees are not suitable .
    I am thinking of suggesting pleached holm oak trees .they can grow in clay and will tolerate the wet to an extent .any thoughts about these ? Many thanks 
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