Conifers on top of stone wall

rojac1000 · May 2019

Hi,

Just wondering if anyone can suggest anything to resolve the issue I have with my wall. Previous owners planted conifers at the top of a stone wall and the stone in the wall are now very loose and will soon start to fall.

I have thought about just putting a fence in front but this will look too plain and I want something a bit more attractive. The trees
themselves are sturdy enough. and give good privacy from next door, however they are a bit sparse at the base so i’m also looking for suggestions on how the improve this. I thought about attaching a trellis or chicken wire plus a climber to the trunks but unsure how this will look in a few years as the trunks grow?

Obelixx · May 2019

Since you have the space, why not leave the wall and the conifers as they are but maybe scatter a generous handful of pelleted chicken manure per metre at the base of the conifers.

Then, dig out a long border as wide as you can - minimum 3' but better 6' - improve the soil with plenty of well-rotted garden compost or horse manure and plant if full of lovely shrubs and perennials to hide the base of those trees and give you a long season of interest from colour and form as well as attracting pollinators.

hogweed · May 2019

I would try to stabilise the wall with cement between the stones. Then do the border as suggested. Or if you don't want a border, plant another lower growing hedge six feet in front of the wall.

Nollie · May 2019

Looks like you have inherited a potential nightmare, those conifers, which look like Leylandi, will only want to get bigger and the previous owner hasn't given them enough space to spread out. The roots are pushing out against the stones, hence them already beginning to topple. I agree with hogweed, you really need to stabilise it first, because stones will likely randomly fall and damage any new planting underneath, or you. It also looks as if your neighbour the other side of the trees has higher ground, so that will be adding downward and outward pressure on the wall as well.

Nothing ever really looks good growing through conifers, it will end up a straggly mess, plus make it nigh impossible to trim the conifers - they will need trimming a couple of times a year to keep under control. If you go for either the mixed border or hedge in front option, leave an access path between the two for hedge trimming purposes.

Asarum · May 2019

I’m not sure they are Leylandii, the growth doesn’t seem upright enough. Have you trimmed them up till now?

Obelixx · May 2019

Doesn't matter. They're conifers and they'll suck up all the nutrients and water and carry on damaging the wall, hence the suggestion to make a bed in front to hide the mess. Agree with Nollie about an access path. Should have mentioned it myself.

Dovefromabove · May 2019

I’m sorry but I think they’re hideous growing out of the wall like that and as they grow they’ll make the wall unstable and the weight of the trees plus wind resistance might result in everything coming crashing down.

In an an ideal world I’d cut them down and get the stumps out, even if it involves a bit of deconstruction and reconstruction of the wall.

Posts and a sturdy trellis fence could then be built into the wall to increase screening if that’s what is wanted.

jackp · May 2019

the problem is likely to only get worse with the wall as these are fast growing trees which haven't been given the adequate growing space required .I would consider either reusing or selling the stones and building an oak sleeper retaining wall about 2.5 feet larger than the exsisting wall and to make sure they have large supporting timbers or steels set into the ground upright and then also the timber in contact with the soil would need protection with a weed control type fabric stapled on to avoid any wet rot .the new bed can be then be filled with any half decent soil but I'd mix it with well rotted manure the final layer could be filled with bark or wood chips which would help hold the moisture in and make weeding easier which will help

Alchemist · May 2019

You can also think of stabilising it with specialist posts attached to 5mm galvanised wire. This way you can have the stone wall whilst stabilising it semi-discreetly. If it’s okay to prevent rockslides up hills, it must be okay here 🤔. Followed by that a nice border as suggested before.

BobFlannigon · May 2019

This depends on how much effort you want to make. You won't stabilise the wall with cement, a tree is much stronger than a little bit of cement. Besides this will look worse not better!

If you like the stones and you like hard work, why not pull them out, mound it up with some top soil, bringing it out slightly, then re-lay the stones and turn it into a bed/rockery. This will create a bit of soil above the tree roots and leave some moisture for a few plants.

You could use ferns to block up the gaps. Conifers are mega thirsty so you'll have your work cut out growing something there (hence the mound).

Nollie · May 2019

If you are keen on keeping the conifers, alternatively, you could rebuild the wall about two feet out from where it is, start with a proper foundation trench and some new stones, mortaring as you go (you could just mortar on the horizontal and inner plane to maintain a rustic look on the outside). Then gradually start using the existing upper stones, building on a slight incline into the slope and building it up higher to hide the bare trunks a bit more, backfill with hardcore, gravel then topsoil up to the level of the roots. Quite an expensive undertaking, but this would be the most stable option. You can then plant in front of your lovely rebuilt wall if you wanted to without fear of collapse.