Earth bank
 

Hello,

I have been deciding whether I should build retaining walls to
terrace my garden, or whether I should try and use earth banks.
The soil is quite clayey (S.Devon). The slope rises about two
and a half metres over about eight metres.

I have no easy access to get in materials, which is why I would
prefer to use what is there (lots of earth). I would also like the
garden to continue looking quite natural, so a giant concrete
retaining wall wouldn't really fit. I did consider using gabions
with a geotextile lining, but they are quite expensive.

So, now I need to decide:
(a) how steep an earth bank I can get away with
(b) what plants would be best for holding the bank together

I realise that (a) is a bit of a "piece of string" question. I've seen
figures of up to 45 degrees for clay soils. I'll be looking to rise
about 1-1.25 metres at the front and back of the terrace.
Anyone got any good examples of their own earth banks?

For (b), I had thought about just grassing the bank, but I'm
wondering if anyone has any suggestions for plants which
will do a better job of "matting" the surface of the bank together?

Thanks in advance,
Al Reynolds

"Al Reynolds" wrote in message
...
Hello,

I have been deciding whether I should build retaining walls to
terrace my garden, or whether I should try and use earth banks.
The soil is quite clayey (S.Devon). The slope rises about two
and a half metres over about eight metres.

I have no easy access to get in materials, which is why I would
prefer to use what is there (lots of earth). I would also like the
garden to continue looking quite natural, so a giant concrete
retaining wall wouldn't really fit. I did consider using gabions
with a geotextile lining, but they are quite expensive.

So, now I need to decide:
(a) how steep an earth bank I can get away with
(b) what plants would be best for holding the bank together

I realise that (a) is a bit of a "piece of string" question. I've seen
figures of up to 45 degrees for clay soils. I'll be looking to rise
about 1-1.25 metres at the front and back of the terrace.
Anyone got any good examples of their own earth banks?

For (b), I had thought about just grassing the bank, but I'm
wondering if anyone has any suggestions for plants which
will do a better job of "matting" the surface of the bank together?

Thanks in advance,
Al Reynolds

If you go for an earth bank then a complete soil cover--ie grass-- will be
better. Adding plants will result in localized "washouts" and it may
eventually collapse.

Al Reynolds wrote:
[...]
For (b), [plants to retain soil inthe bank] I had thought about
just grassing the bank, but I'm
wondering if anyone has any suggestions for plants which
will do a better job of "matting" the surface of the bank together?

I'd say that grass, though a bit dull perhaps, would do a better
binding job, and do it quicker, than pretty well anything else. You
can grow a lot of low-growing wild flowers such as primroses in it
for variety. If you use grass, then convenience and safety of mowing
will be the real decider for the angle of the slope. I want to stress
safety he not just the potential for the more obvious dangerous
accident, but longer-term considerations like strain on your back.

So if it's within the budget, a good collection of ericas or heathers
would be very attractive. Once established they'll hold the soil well
enough, especially if you lay down a landscaping mesh; and would need
serious weeding only for the first two or three years; and would
never need mowing, of course! You'd have to be prepared to shell out
a pound a plant, though, unless you could find a bulk source.

Mike.

On Tue, 12 Oct 2004 14:54:16 +0100, "Al Reynolds"
wrote:

Hello,

I have been deciding whether I should build retaining walls to
terrace my garden, or whether I should try and use earth banks.
The soil is quite clayey (S.Devon). The slope rises about two
and a half metres over about eight metres.

I have no easy access to get in materials, which is why I would
prefer to use what is there (lots of earth). I would also like the
garden to continue looking quite natural, so a giant concrete
retaining wall wouldn't really fit. I did consider using gabions
with a geotextile lining, but they are quite expensive.

What about going a step or two beyond the terrace idea and using the
slope as the basis for creating an interesting and varied topography?
Very steep in some parts - possibly with curved drystone walling or
rockery outcrop to hold those. Curved path, turning into steps where
it gets too steep, sloped lawn in other parts, sloping beds for plants
where it's somewhat less steep. Hide a path with no steps somewhere
for barrow/mower access.
I wonder why those of us with flat gardens want slopes, those with
slopes want it flat? I'd love to have more slopes to design around in
this garden.

=================================================

Rod

Weed my email address to reply.
http://website.lineone.net/~rodcraddock/index.html

"Mike Lyle" wrote in message
...
Al Reynolds wrote:
[...]
For (b), [plants to retain soil inthe bank] I had thought about
just grassing the bank, but I'm
wondering if anyone has any suggestions for plants which
will do a better job of "matting" the surface of the bank together?

I'd say that grass, though a bit dull perhaps, would do a better
binding job, and do it quicker, than pretty well anything else. You
can grow a lot of low-growing wild flowers such as primroses in it
for variety. If you use grass, then convenience and safety of mowing
will be the real decider for the angle of the slope. I want to stress
safety he not just the potential for the more obvious dangerous
accident, but longer-term considerations like strain on your back.

I already have to harness myself in to mow the bottom of the garden;
at the bottom of the slope is a ten foot drop onto concrete. I was thinking
of not mowing the grass on the sloping sections - a kind of meadow effect
which I'll strim once a year.

So if it's within the budget, a good collection of ericas or heathers
would be very attractive. Once established they'll hold the soil well
enough, especially if you lay down a landscaping mesh; and would need
serious weeding only for the first two or three years; and would
never need mowing, of course! You'd have to be prepared to shell out
a pound a plant, though, unless you could find a bulk source.

A neighbour has St. John's Wort on an earth bank at the front of the house.
Would that hold the ground together well? My worry would be that it would
spread into the lawn too easily.

Thanks for the comments,
Al

"Rod" wrote:
What about going a step or two beyond the terrace idea and using the
slope as the basis for creating an interesting and varied topography?
Very steep in some parts - possibly with curved drystone walling or
rockery outcrop to hold those. Curved path, turning into steps where
it gets too steep, sloped lawn in other parts, sloping beds for plants
where it's somewhat less steep. Hide a path with no steps somewhere
for barrow/mower access.

Good point - although even with this terracing there will still be quite a
lot of slope - at the highest point in my garden the grass is above the
roofline of the house!

I wonder why those of us with flat gardens want slopes, those with
slopes want it flat? I'd love to have more slopes to design around in
this garden.

;-) V. true. If I had a flat garden I would want slopes. As it is, I just
want to create a reasonably sized safe play area for the moment, as the
only flat area in my garden at the moment is the path to the compost
heap.

Cheers,
Al

I would worry about having any sort of retaining wall with a drop on one
side and shrubs/bushes along the top,without it having a fence along the top
edge. Bushes are great for young children to play amongst, and a sudden drop
cam be very dangerous.


--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

"Al Reynolds" wrote in message
...
"Rod" wrote:
What about going a step or two beyond the terrace idea and using
the
slope as the basis for creating an interesting and varied
topography?
Very steep in some parts - possibly with curved drystone walling
or
rockery outcrop to hold those. Curved path, turning into steps
where
it gets too steep, sloped lawn in other parts, sloping beds for
plants
where it's somewhat less steep. Hide a path with no steps
somewhere
for barrow/mower access.

Good point - although even with this terracing there will still be
quite a
lot of slope - at the highest point in my garden the grass is above
the
roofline of the house!

Both the ground floor and the first floor of my house are at ground
level, and the garden rises yet further behind the house.

I wonder why those of us with flat gardens want slopes, those with
slopes want it flat? I'd love to have more slopes to design around
in
this garden.

;-) V. true. If I had a flat garden I would want slopes. As it
is, I just
want to create a reasonably sized safe play area for the moment, as
the
only flat area in my garden at the moment is the path to the compost
heap.

I have a vey steep garden, the bulk of which was terraced with York
sandsrone retaining walls, all built with the kind help of my
neighbour, for whom no amount of praise is sufficient.

Franz