Clay soil and rubble layer under garden, how to plant shrubs?

[Blackberryjammin]

We've just moved and I have been trying to dig some flower beds. The soils are clay so sticky and need improving but it also seems that 30cm down there is just a layer of rubble under the front garden with the odd massive rock in it too. What can I do? I've removed the turf for a huge flower bed and now can't dig down further than one spade depth. Can I just pile more soil on top to create a mound? Will shrubs grow in it?

Raised beds are not an option as its such a large area. Neighbours have shrubs growing in their gardens and we have some trees.

What area are you. Clay soil is quite fertile, but if you are in an area with a lot of rain, drainage can be a problem. I garden on clay and I use a company called Compost Direct . They have a huge range of compost and mulching. Improving the soil would be my first priority.

Compost, compost and more compost... And when you think you have added enough double it. Add wood chippings and dig the whole lot through

I put about a 20cm layer on every year ....

Thank you @Rictasmorticia and @MyAgileHedgehog so do you think I can get away without digging out the rubble and just piling more compost on top?

It is hard work I know, but it really does pay to remove as much rubble as possible. Builders are terrible for leaving a mess of broken bricks and whatnot everywhere, bulldozing it flat and just dumping some topsoil over the top to hide it all. Mortar and concrete are the worst as they are very alkaline and will affect the growing conditions for anything you plant in there. The best time to do it is before planting shrubs as you won't be able to do it after.

Get as much as you can out and as much soil improver as you can in then start selecting your roses. We had the same and roses seem to thrive in our garden.

When was it built? New builds are notorious for having rubble under the soil. Have you checked the soil ph with one of the kits you get on Amazon? The rubble can make soils alkaline and that would restrict what you can plant.

A garden fork is a much better tool than a spade in the conditions you describe. The tines will get between the stones and you won't feel like you're coming up against a brick wall so much.

Did out as much of the rubble as you can. (Often people will take it away for nothing if you advertise it on Marketplace as you might have to pay to dispose of it at the recycling centre. Then improve the soil. The old saying is 'Spend as much on the hole as you do on the plant' is really true.

Clay soil suits lots of plants. Have a look at Crocus or the RHS website for lists of things that will thrive in your garden.

We are in a NB and have done lots of planting (with lots more to come).

Heavy clay but no rubble to speak of, just plenty of flint & stone which our area is known for.
When planting we dig out as much as possible and put in plenty of compost & soil, rotted manure, liberal amounts of soil improver and top with mulch/bark.

All good so far.👍

My garden was like that when I started 40 years ago. There wasn't just rubble there was also a seam of limestone about 10" down. It was more like mining than digging when I made flower beds. I planned the whole garden and dug out beds taking out as much rock as possible and added tons of manure etc. I built walls with the rocks.
In between the beds where I was just putting grass I didn't remove the stones so it's near impossible to dig a new border.
I have a beautiful garden now but if I was doing it again I would get a bloody big digger and excavate the lot first.

Mid 90's. It's not all rubble, lots of large bits of rock from an old quarry. Limestone I think so would likely be alkaline.

This sounds a bit like ours.

If you don't want the hassle of trying to dig it all out, there's a method that's served me well on heavy clay/stony ground. When planting a shrub, dig a much bigger hole than you need. Then backfill with compost or soil improver. And mulch like it's going out of style.

Thanks @moggerhanger I think this is a good plan. We have dug out loads more rocks today. It's more rocky than rubble. I've also dug in lots of soil improver and am going to start with some fairly hardy shrubs and do as you say plant in holes with compost. Then just smother the lot in mulch and bark and hope that the birds haven't eaten all the worms.

Check out these guys, they encourage you to work with what you've got: https://www.rhs.org.uk/garden-inspiration/get-gardening/changing-what-it-means-to-be-a-modern-gardener

There's loads of plants that thrive on alkaline soil. Avoid anything like azaleas etc, as they'll hate it.

You can definitely pick stuff that's tough as old boots, but still looks nice.

The whole of our front garden is basically builders rubble and clay. The back obviously clay and lots of large limescale stones. It's a nightmare.

Depends how deep down it is. I have to dig it all out with a trowel every time (too many broken bricks/stones that I can't dig with a space), to below where plants will grow. We now realise this is a lifetime home, so if I'd known that, I'd have had it professionally dug out and decent compost put on top.

Look for plants that can cope with poor quality soil - as said above azeleas are a complete no, also pieris. One that have coped with our soil are spirea, hygrangeas, ceonothus, euonymus (sorry, you might have to excuse some spellings). We have quite a few plants that look healthy enough, but haven't grown to their full size, even 8-10 years later.

I have similar in my back garden. Went to dig a hole and hit rock very soon. Something I've used to help is a very powerful hammer drill and strong drill bit and safety goggles. I don't aim to get all the rock out just break it up so that the plant roots can get in between the gaps to the soil. It's heavy work but doesn't actually take that long.