planting trees in heavy clay wet soil.

[Ashbrooke]

Hi, I've got a job working on a housing estate and we have settled on a planting plan for a slope composed of heavy clay. the birch originally planted on the slope have not done well.

 

I have tested the soil and it is within normal ranges for most nutrients and ranges from 7-8 ph. the only issue is drainage with water currently sitting 12 inches below the surface in some areas.

 

weeping willow is being planted to attempt to dry the site out, along with some rowan (client is very keen on the rowan)

 

Am i correct in thinking to use very little organic matter in the hole with some sand to help break up the clay?

should i plant the rowan on a slight mound to help with drainage?

 

Thanks for your help.

[difflock]

I understood Alder to be the best for wet clay sites, and whilst not the visually most attractive, supposed to be very good for wildlife, I know the Alder I planted in a wet dour clay hole are properly thriving.

good luck

marcus

[Ashbrooke]

yeah alder is supposed to be good. the committee like the look of the weeping willows over the alder.

[Ashbrooke]

we are going to plant the willows in groups of 3 and pollard them when ready to start a 3 year pollard cycle.

[TimberCutterDartmoor]

Be VERY careful about PZRI distances...

[biggarlogs]

Be VERY careful about PZRI distances...

 

For the uneducated ones ,please translate PZRI. Ta

[Goaty]

Rowan like free draining soil that gets regular rainfall. Hence mountain ash. More a cumbria area tree. They hate sitting wet in clay then baking dry.

Hornbeam should do ok as alder. Willow are a bit of a high maintenance tree in urban areas and have a bad boy reputation. Taxodium and metasequioa. Juglans nigra not regia can do ok in clay.

Holly oak and sessile oak. Probably other oaks as well.

 

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[timberbear]

I've just planted some 600 trees on a very wet site. I've opted for a lot of alder and downy birch with a mix of rowan and alder buckthorn. The idea is to coppice them in about 15yrs so they never reach a height when they will be prone to toppling on a steep wet slope.

 

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[TimberCutterDartmoor]

For the uneducated ones ,please translate PZRI. Ta

 

Sorry. "Potential Zone of Root Influence"

 

Willow, pop etc in clay soil?! Hmmm.

[Goaty]

Just reread o.p.

The drainage issue will be. "Not my problem" from the construction industry. All year round paddling, trampling with machinery then a cosmetic 300mm of structure less soil.

In horticulture and agriculture it would be subsoiled to heave it. Then air and water would flow through the lot.

Even if you augered 20ft deep holes and backfilled with premium growing media. The water would accumulate in them.

As good as your intentions are to prune the. Willow. It will only maybe get done once. Its likely your client wont be prepared to keep investing. Ive planted several woodlands and haven't got round to even visiting them yet.

Just been realistic.

 

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