Creating and Planting Significant Banks

Soil banks ... not usurious ones!

I have two large piles of spoil. One is concrete broken up from a leaking pond, years ago, piled up in a corner waiting for a purpose ... or crushing.

The other is the heavy clay that came out of some footings - much more than expected after the engineer <spit!> decreed that I needed 3M foundations because of the close proximity of a Lime tree - the Lime tree being a pleached hedge ...

So ... I wondered about creating a garden "room" with a bank around it. I'm thinking something fairly substantial so that when inside it there would be planting that added considerable height, and enclosed the area - amphitheatre shape, if you will. The ground around here is pancake flat, so I have no natural undulations to take advantage of.

This idea is borne out of a visit to Compton Acres. I'm not a fan of Japanese Gardens, outside of Japan (other than Kazuyuki Ishihara's gardens at Chelsea ) as having lived in Japan for some time I find the ones in the UK a pale imitation ... however ...

Compton Acre's Japanese garden is arranged around a pond. Its not easy to see from this photo, but there is a winding walk around the water's edge, with rising ground behind (all the way around the pond). Behind the "bank" they have planted pines (Scots probably), which give the impression of height (i.e. they may well be planted behind the bank, but at the lower level, but still create the illusion of height).



This is from some stepping stones in the middle, looking back at where the photo (above) was taken. It gives a bit of a clue to the rising ground:



and here is an example of the path along the edge of the water. The water is about 10' away to the right, but (at this point along the path) craftily hidden by some planting. The "outer" bank is on the left, including the Pines, planted behind the bank, giving the illusion of rising-ground:



At the far end (i.e. relative to my first photo above) is a more significant "mound", which provides the opportunity for a water fall:



Bit tricky to see in the photo but:

To the right of the waterfall, and slightly above it, is a light coloured round stone with an emblem on it Halfway between the two, higher up, at the top of the bushes where the trees start, there is a dark grey "box". This is an obelisk, and from the right of this photo there are steps up to it:



I reckon its about 20' up, this is the view back down from the top



When you walk up to the top the Obelisk is clearly on top of a "mound". Peeking between the bushes you can see the roof of a building nearby!

So the question is: can I use my pile of clay, and concrete, to make something like this?

Digging out a pond will give me more clay ... and I can make the pond-side path "lower" than my current ground level - i.e. if the water level is 2' or 3' below the current surface level that will help me to maintain the water level in summer, and will help me by exaggerating the "bank effect".

I am thinking to use Gabions filled with the concrete waste to hold the banks together.



But will anything grow in the pure clay? I can make planting holes, deep if necessary, of topsoil ... but it will be dry as a bone in summer being raised up, and once the shrub roots escape the topsoil holes they will be into heavy clay ...

The size of the Compton Acres garden is surprisingly small - judging by Google Satellite images



Light blue is the pond, Brown the pathway around & across the pond, and the orange is the steps up to the obelisk.

I reckon my "plot" is 125' long x 50' wide - looks like Compton Acres Japanese garden would fit in that space??

 

I found a photo of an old postcard, shows the heighth differential and "bank-y-ness" better

 

You say your land is flat Kristen, have you got enough soil to create a knoll or two or even three?
With gentle slopes between them I think you could create something easier on the eye than with a bank enclosed 'room'.

 

I think using the the concrete in gabions is a great idea. Depending on how much soil you intend to shore up with them it should be a great support. I've seen huge walls of them along motor ways holding up 20ft high soil banks. I would get a structural engineer in though to discuss how to hold them in place as the last thing you want is a landslide when we get a bit of heavy rain.

I would fill a couple with glass bottles too, thread some lights into them so they glow at night. But that's just me.

Have you ever visited RHS Hyde Hall? They have a garden which is on the side of a slope, which had a few trees planted in it. I think they were eucalyptus trees and a lot of the plants were from New Zealand. But well worth a visit anyway as the whole garden is on clay soil and doesn't get much water anyway.

 

I probably have enough soil, but my garden is not that type, its a series of rooms (with hedges around each one). I started off trying for open-style and long paths / island beds / etc. but decided that "rooms" was the way I wanted to go.

 

No ... and its just down the road from me :( but I've seen photos of the slope that you mention, so I can see what you mean. I'll go and have a look, thanks.

Driest part of the country, so will be interesting to see what they have done. Tempted to jump in the car now (ought to do some work though!)

 

Compton Gardens is stunning

 

Just throwing this one out there but have you considered a LARGE Rockery @Kristen ? I've yet to find a picture of what I'm thinking of...

 

Not my thing, sorry :(

Well ... based on past experience I probably should say "Not my thing yet"

 

I get you....Rockeries have never been my thing but the last couple of years I've visited a couple of places ,one in particular was Parcevall Hall gardens in the Dales,it was quite impressive and on a steep hillside thus getting me started on a collection of these which are lumbering up the drive


All I need now is a few more ton and a Hillside...

Sorry I digress

 

What plants are you thinking of, Kristen? Bear in mind that most 'Japanese' plants prefer acid soil, so you'd need to substitute nearly everything with neutral or lime-tolerant plants, by which time it wouldn't look anything like Compton Acres!

 

Not sure what I would do for Japanese Acers - maybe they would cope on my (alkaline) soil.

For Rhododendrons I was already planning to plant some Inkarho varieties, so this would just be the "site" for them.

I might use Laurel, round the back, to make a thick non-see-through surround.

 

Sorry for the delay in replying The bit that worries me is buried old concrete. Will it leach lime into the surrounding soil, especially into lower levels? Could the gabions be sealed under sheet plastic?
If you know any local cattle farmers or equestrian types it would help to incorporate as much well-rotted FYM as you can get hold of. It will improve the clay and help acidify the area. I know it's preaching to the converted, but the more preparation you put into the area, the better the results will be
If you need 20 or so Acer palmatum 'Sango kaku' seedlings, give me a shout

 

Looks a bit tricky for the wheelchair in future years.
Just thinking ahead.

 

I think this is a bit too cautious personally. My garden is full of buried concrete and asbestos and it doesn't bother me personally.