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Advice for planting trees in clay soil on a slope?
We've added a few trees to our garden over the last couple of years. The garden is on a slope and the soil has a high clay content. Up to now, we've gone for bare root trees and used the "slit" planting method, for fear that if we go for the more traditional "pit" planting method we'd effectively be sitting the root ball in a poor draining clay bowl. Thus far, the slit method has worked for us.
Now however I'm looking to add an ornamental cherry tree and I'd prefer to get one that's a little older and more developed, therefore not bare root. I guess this would force us into using the pit planting method.
Do you think this will be viable in our garden? Do you think our concern about the pit method in clay soil is unfounded? Are there any steps you'd take to give us a better chance of success? (We're on the wet coast of Scotland BTW, so long periods of heavy rainfall).
Now however I'm looking to add an ornamental cherry tree and I'd prefer to get one that's a little older and more developed, therefore not bare root. I guess this would force us into using the pit planting method.
Do you think this will be viable in our garden? Do you think our concern about the pit method in clay soil is unfounded? Are there any steps you'd take to give us a better chance of success? (We're on the wet coast of Scotland BTW, so long periods of heavy rainfall).
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I would definitely consider creating a proper space for it, and amending the soil well enough to get it established. You could create a raised area -anything will do for that - rocks/timber/brick etc] of about 3 feet in diameter, and add plenty of organic matter which helps enormously with drainage here, and that will also improve the soil generally for your tree.
Where are you intending putting the new tree? A pic of the site will help a bit if you can do one - the icon that looks like a hill is the one for uploading, and if you can keep them at around 1 MB or smaller, they load better.
I live in west central Scotland - not where that photo is...
Hi, tlhouse
Planting an ornamental cherry tree in clay soil on a slope in a wet climate like the west coast of Scotland can present some challenges, but it's definitely possible with proper preparation and care.
Before planting, consider amending the clay soil to improve its drainage and aeration. Adding organic matter like well-rotted compost, aged manure, or peat moss can help break up the clay and create a more favorable environment for root growth. You can mix these amendments with the existing soil in the planting hole.
If you're particularly concerned about drainage, you can create a raised bed for the cherry tree. This can elevate the root system above potential pooling water during heavy rainfall. The raised bed can also aid in improving soil drainage, especially if you use a well-draining soil mix.
Select a planting site that receives adequate sunlight and is away from areas prone to waterlogging. Avoid planting the tree in low-lying areas where water tends to accumulate.
The key takeaways are -
- don't excavate deeper than the root ball (this can cause settlement and the tree can end up sitting too low in the ground).
- on poorly drained soils sit the root ball so the surface is 25% higher than surrounding levels and mound up to it with existing soil
- don't import new soil or compost into the tree pit, just cultivate the existing soil and use that (avoid creating a sump and get the tree's roots used to the surrounding soil rather than cossetting them in a rich pocket of compost)
- use mulch but avoid the mulch sitting too deep over the surface of the root ball and avoid contact with the stem
This is definitely one of those 'more than one way to skin a cat' types of thing, but I think there's a lot of merit to the approaches above. As a gardener the desire to ameliorate soil when planting is hard to ignore, I would probably add some enrichment but work it into the surface, rather than digging it in deeply.
If your planting holes are going to be large, you could dig them first and then see how well they drain away, on a slope you have the option of adding french drains or perforated pipes to help carry water away to lower ground.
Here's a quick shot of the site we're considering for the tree - the fence verticals show the slope:
Just clear the area of all the turf where you intend planting, and prep it well, as myself and @Loxley have described. You can create a raised area on the lower side, using anything that suits, to make it easier, but I don't think you need to worry too much.
It's still not clear exactly which bit of the site you intend using though, but that won't be a problem anywhere in there - if you're worried, keep it on the right side of your pic where it's flatter.
People tend to think the bottom of a slope will always be much wetter than the top, but that's often misleading. The top of hills would never be wet and squelchy if that was the case.
Rainwater works directly into the soil, and it's only when it's long term and consistently wet that it gradually makes it way 'down' and creates boggier areas in the lower, flatter parts, or ends up in burns and tributaries. It's the soil structure and it's drainage that matters most, hence improving it before adding any plant, whether it's perennials, or shrubs and trees. That's what will determine the success of your plants. A group of trees will succeed more easily than a single one too, simply because they'll take up plenty of moisture.
I don't know which bit of our west coast you're in either - west of me is quite different from the 'proper' north west, but it should be ok for something as tough as an ornamental cherry. Prep the ground with organic matter over the next couple of months and then plant.
I live in west central Scotland - not where that photo is...