Preparing clay soil for a tree

steve390

Hi! I'm a fairly amateur gardener taking on the job of learning how to manage the garden at our cottage and restore some trees and plants that were removed by previous gardeners. The soil around the cottage is clay, it having been built on marshland, but in various places the clay soil has been worked to make it usable for planting. However in one 3 by 3 metre square corner where I want to put a fast growing tree and some plants underneath, the clay soil has some small stones on the surface and some sand underneath (see pictures) so if I were to mix the soil up a bit more thoroughly, would this be sufficient drainage for plants?

Thanks in advance!

Steve

Topbird

Those don't look like normal garden stones to me.

I'd dig a hole and see what's underneath first. Are you sure it's not some sort of drainage / soakaway area?

barry island

That looks like a soakaway of some kind is it very wet in that area?

BobTheGardener

I agree, that looks like bought-in gravel so needs further investigation - a small 1ft square hole about a foot deep should provide some clues.  It might just have been a paved area with the pavers replaced by gravel at some point (if so, the sandy layer beneath won't be much more than 6 inches deep before you hit bare earth.)  If there's mostly gravel at a foot down or deeper, it is likely a soakaway of some kind.

steve390

Thanks for all the feedback!

I investigated a bit more. The gravel is indeed bought-in and I omitted to clarify that. I dug down and it appears the gravel is entirely on the surface. Just beneath is a thin layer of sand and below that, clay soil. So it appears that this was a paved or walk area at some point rather than a soakaway. The area isn't generally wet.

Greenbird

I'm not an expert, but I once planted an ornamental cherry straight into similar soil and it grew from 1m to 4m in 5 years before I moved house. I just broke up the clay and mixed it with half a bag of garden compost - no special treatment.

My new house is on extremely heavy clay and most the trees in the surrounding area are Alders. So i'd guess that an Alder would be fine on your soil - too big for my garden unfortunately.

I'd also assume Birch would be fine was they seem to grow anywhere in the wild easy enough. 

raisingirl

Alders will grow in bogs. There are plenty of trees that will grow in clay soils that aren't actually under standing water (the whole rose family, for example). Trying to improve drainage at the surface is unlikely to improve the tree's experience of life - better to find a tree that likes your conditions and just let it get on with it. What sort of tree did you have in mind?

wild edges

If you're not fixed on a type of tree then it's always helpful to just look at what's growing and thriving locally and pick something from the same family.

steve390

Thanks to everybody for the input. I'm not fixed on the tree type but I would like something that grows reasonably quickly, would thrive in clay soil and would also provide a habitat for birds (either fruit or nesting) so I was considering willow. I would also like to have some flowers growing around the base as otherwise it looks a bit bare but I'll need to do some separate research into that. The area is exposed and gets a quite a bit of sun during the middle of the day.

So based on this, should I just churn the existing soil to mix in the bought in gravel that is on the surface into the soil itself before planting as otherwise it looks a bit unattractive. I have some topsoil spare I can spread over the top - is that worth doing?

floralies

If you are thinking of planting a willow bear in mind how far it will be planted away from house and drains. Willows take up a lot of water and spread their roots far and wide to reach it. We had a willow that was planted before we moved here and only found out when the roots encroached into the raised beds some way away taking the water from the irrigation system.

Posy

Is your clay very waterlogged? If it stays very wet all winter you will need to choose a tree that will tolerate this. There are many willows; some grow to be enormous but others have a more bushy habit and can be cut back hard. I like cornus for winter colour because they like clay, but they are not trees!