Killing Yew with Feet in Clay

October can be a peak month for planting and digging.
You’ve got your Spring Flower Bulbs going in the ground, a flurry of pot grown plants from soft fruit to ferns (many of which are on discount in Autumn, as newsletter subscribers know), and gardeners on their ‘A game’ will work that soil in preparation for Winter planting anytime from November to March.

Sure, it has been a reasonably rainy start to the month, so major digging operations might wait for the dry weather forecast in a week or two: the aim is to get the job done when the soil is not full of water, ideally on a nice sunny Autumn day.
If you wait until planting time in Winter to dig holes for trees and trenches for hedges, or to work over new beds, you might have a much tougher, wetter, colder, heavier, slipperier job, especially on clay soils.

This ramble is in honour of Yew hedges. It applies to all plants that need a well drained soil, but Yew is both very popular and on the expensive side for hedging. So, we receive a number of claims about Yew from our customers every year for our Replacement Guarantee.

Did all their Yew hedging die because we sent them a special batch of dead plants, and everyone else got plump, happy, thriving Yew that took off like a very slow green rocket in gardens all over the UK?

No, dear reader. It was murder.
You can do anything you like with the plants you buy from us, including kill them, and we won’t judge you. We’ll be awfully nice about it, and give you some free plants.

How do people kill their Yew for fun and profit? Number one reason is drying out and not being watered. That’s true for new plants in general.

The other big reason is being overwatered to death, which mostly happens on clay soil that was improved in a misguided way by digging lots of stuff into it – compost, sharp sand, grit, pieces of wood.

If you dig a hole or trench in clay, it fills with water when it rains, staying full for long enough to drown roots, especially new ones. The fact that you dug in a lot of compost to the hole won’t change anything: the hole is effectively a tub full of totally wet muddy-compost.

If your ground is well drained, you can do what you like: dig a trench, improve the soil, water often (maybe with an irrigation system), and use the largest plants you want. It’s all fine.

If you have heavy clay soil (sticky grey, blue or yellow), the good news is that you have richly fertile soil.
There is no need to improve it with anything, only to break it up and loosen it up for larger plants that need planting holes (i.e. they are too big for slit planting). And October is a good time for that work.

On badly drained clay soils, it’s better to buy the smaller sizes available, slit plant them wherever possible, and add organic matter as mulch on top of the soil after planting.
Afterwards, only water the new plants when the soil is drying out. Soak the soil thoroughly, then do not water again until the top 5-10cm of soil is dry.

By Ashridge Support

Ashridge Nurseries has been in the business of delivering plants since 1949.

15 comments

  1. Holly Nairn says:

    Brilliant advice on your website. I planted a yew hedge last year in a manured trench on clay and have watched it bronze and suffer – we have since put in more drainage, will add a foliar feed this spring and have our fingers crossed. I watched that very same programme last year and shook my head in disbelief at the presenter’s poor planting advice. I am about to plant a few more hedges on heavy clay soil and will do it your way, planting into slits adding rootgrow to the roots as I go, and mulching after. Look forward to better results this time. Only wish I had found your website sooner. Please continue your wonderful website – it is so very much appreciated. From fans in Central Scotland.

    1. Edward says:

      Hi Holly and a big hello to Central Scotland!

      To be fair on that presenter, it is perfectly good advice if your soil is well drained. Considering how many British gardeners have heavy clay, though….

      Back to your hedge: yew often bronzes after transplanting, so that shouldn’t be an issue, but a foliar feed will only work on green leaves.

      You might consider replanting – from now until early March is fine, on a day when the soil isn’t frozen.
      I can’t really judge without seeing it, but if you can see that it’s just too wet in the trench, then putting the clay back now is the best choice.

      As for future hedges, a plastic mulch sheet is worth a look – it becomes hidden in a couple of years and does an amazing job of keeping out the weeds & preserving moisture in summer with no work.

      You can tip the mycorrhizae into a bucket of water & dunk the roots in it immediately before planting. Pour out any excess on to the soil around the new hedge.

      Have fun!

  2. Hello all,

    I have just read this article . . halfway through digging a 49 foot trench in heavy clay – by hand!!

    The trench unearthed about 20% building rubble.

    Please can I have advice on what I should do?

    Put the soil back? Put the rubble back? Stamp it all down and cut slits?

    Advice gratefully received.

    I am ordering the plants this week . . .

    Chris

    1. Edward says:

      Hi Chris,

      Well, you are in a great position to do an experiment!

      I would pull out big bits of rubble and put it all the rest back in, churning in some well rotted manure if you have the energy (this will be good if there is quite a bit of rubble to remove).

  3. Katrina says:

    Hi,

    I am about to plant at 60 meter hedgerow in clay soil picked full of Cotswold Limestone and old tree roots. Given the length of the hedgerow (I am looking to plant Laurel) and stones etc ( took hubby and myself to dig a hole 250mm x 300mm for planting half a day in the same location)is there a better way than digging by hand?
    Any advise gratefully received

    1. Edward says:

      Hi Katrina,

      There are all sorts of small & large rotovators for hire, you can even hire a tractor sized version. Much faster than slogging by hand.
      My question would be, do you really need to?

      With heavy clay, it’s best to make one slit in the soil per plant with a spade, sweep a bareroot plant roots in and firm it all closed.
      Don’t bother making a great big trench and changing the soil. Keep the clay. If you do rotovate, just mix in some well rotted compost/manure as you go over it at the end.

      If the stones are really bad, then yes, you probably should rotovate – if you can’t stick a spade into it, you can’t plant in it!

      Cherry laurel would not be my first choice for alkaline clay soil, portugal laurel would be better suited and holly will really thrive on it.

      Good luck!

      Ed

  4. Katrina says:

    Thank you so much for your help! we have tried spades pick axes and even our own hands to dig in our ground there are so many stones – and large ones at that ! so rotivator it is. Thank you for your advise regarding species, we have already planted a lot of holly and so will take a look at the portugal laurel now.

    Thanks again
    Katrina

    1. Edward says:

      If the ground is that bad, I recommend hiring a pro to do it. They will have a bigger, badder rotovator than the ones you can get in a hire shop, and will use it expertly. It will be more expensive, but you could get someone to do in a few hours, whereas you might need to hire the machine for a few days to do a good job.

      The best hand tool is probably the azada shaped mattock, which is much lighter than a pick axe and better for moving soil around. Wet the soil well the day before you dig to make it softer. Good luck!

  5. Penny says:

    Hi
    I have behind a small retaining wall 3ft deep x 1.5 ft wide clay soil with gravel on top for decoration. The total length is approx 30ft and want to plant hedging – probably Laurel of some kind. Would it be easier to have troughs built and inserted into the clay then soil then plant the Laurel.
    Any info would be appreciated 🙂

    1. julian says:

      If it is real “potter’s clay” the laurel will struggle to establish and troughs would be best. If is is just heavy soil then plant straight into the ground.

  6. Caroline says:

    I planted a yew hedge three years ago and keep loosing plants in two areas of the hedge. It appears that we have blue clay! I love the well established part of the hedge and would love to have the whole hedge yew but do not want to waste more money on filling the gaps if yew will not grow there.
    Any advise will be gratefully received, even a suggestion of what shrub to put in the six foot gaps if I have to give up on the yew.

    1. julian says:

      Yew hedging plants do not like clay – you are right. It is not so much the clay actually as the bad drainage. As you have seen, once yew plants are established in clay, they grow away really well. As a last resort, I would be inclined to plant barerooted yew hedge plants instead of potgrown or rootballed ones. Plant small plants, do NOT dig or improve the soil. Instead, plant them down the back of a spade. Watch our video on Planting Country Hedging to see how this is done. They will suffer less from bad drainage this way and once established will catch the other yew plants up quite quickly.

      Good luck

  7. Clara says:

    Hi Julian

    I have bare root yew (20/30 cm bare root) that I tried planting down the back of the spade as you advised in clay/heavy soil. However, some of the bare root yew have such large and long root systems, some roots as long as 60 cm that I don’t quite know how to plant them.

    Do I trim the roots so that they are more manageable at about 30 cm long?

    Do I just try to jam all the roots behind the back of the spade?

    Any advice given would be greatly appreciated.

    Thank you.

    1. root says:

      Yew in heavy ground…. thanks for your email. The first comment is to make sure that you have clayey soil. If you have good drainage you can dig holes and plant in those. However if you are on clay then you need to follow the principles involved in planting down the back of a spade…

      1. Under no circumstances trim the roots unless they are damaged. They are a food store and help the plant into growth in the spring.
      2. The point about slit planting is that when the slit is closed up there is no hole full of porous spoil that will form a sump and cause the roots to sit in water all winter (which is bad for them). So if the roots are too big for a slit, I would be inclined to remove a whole “clod”, plant the yew against one side of the hole you have created, and then fit the clod back into the hole and firm it down.

      You will get the same effect that way.

      Good luck
      Julian

    2. Max says:

      Yeah, I had the same problem with slit planting on clay as suggested in the video… due to the size of the bare roots of the Yew hedging supplied.

      Difficult to take out clods, because I was planting through cuts in the agricultural membrane as suggested in the video.

      In retrospect I felt I should have purchased your ‘smallest’ size bare root Yew plants, rather than the medium sized, as their smaller root systems would have been more practical to plant down the back of a spade slit trench.

      All a bit of an experiment, 40 plants put in rather wet clay ground mid December (the rain has been horrendous recently) and we’ll see how they do.

Leave a comment

Your email address will not be published. Required fields are marked *

Back to top