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Native groundcover for hard clay soil
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Posted by silentC NSW Aust (My Page) on Mon, Dec 12, 05 at 0:14
| I've got a couple of battered-back embankments that I'd like to plant out with some Australian native ground cover and some shrubs or small trees. The batter is about 35 degrees, you can just walk up it. All of the top soil (what there was of it) is gone and the ground is composed of clay. This clay is very hard when dry and holds water. If you dig a hole and fill it with water, it will stay that way for days until it evaporates.
I have no idea whether it's even possible to grow something in/on this stuff. The top soil was very thin and the block was covered in saplings when we bought it, so I guess it's feasible but without top soil at all?
I'm planning to put a low wall at the bottom (300mm sleeper on edge) and a pine log at the top.
Pigface has been suggested to me, any other suggestions welcome.
Thanks! |
Follow-Up Postings:
RE: Native groundcover for hard clay soil
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| Eremophila debilis (Myoporum debile) would be hard to beat. It's a local native in western Sydney heavy clay soils and appears to be very drought tolerant as well. |
RE: Native groundcover for hard clay soil
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| Looks like just the thing. Thanks Tony. |
RE: Native groundcover for hard clay soil
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| Hardenbergias are pretty tough once you get them established |
RE: Native groundcover for hard clay soil
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| Dianella is ideal. Scatter a few Lomandras as well especially Tanika. |
RE: Native groundcover for hard clay soil
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| The plants I list here are specific to the Melbourne region however there wil be no doubt other species from the same genera that are endemic to NSW and have the same or similar growth habits. Plants that I would try as ground cover would be: 1) Acaena novea-zelandiae or Bidgee Widgee - forms a very thick weed suppressing carpet and readily self seeds. One plant will cover up to 2 square metres. It has interesting globular flowers/seed heads standing above the matted foliage. 2) Salt bushes, e.g. Rhagodia, Atriplex and Einadia etc. 3) Pea or Fabacea shrubs, e.g. Eutaxia microphylla, Eutaxia diffusa, Glycine sp, Desmodium sp, Kennedia prostrata. You could try some Hardenbergia violacea however my experience of it is that it tends to prefer stony well drained soils rather than clay. Suitable accent shrubs and trees would be: 1) Acacia pycnantha or Golden Wattle. Around Melbourne they grow in the same sort of places as Hardenbergia violacea, however I have grown some in clay soils and they seem to do OK mostly. It is a pretty adaptable species and is not our national floral emblem for nothing. 2) Myoporum viscosum or Sticky Boobilla. Tends to grow in a similar fashion to Cyphrus, i.e. a thin skin of live foliage and bear branches to the trunks beneath, so they can also look a bit rangy if you don't prune them once or twice a year. The dark dull green leaves and masses of white flowers make them worth this effort. 3) Indigofera australis or Austral Indigo. Also tends to get rangy if you don't prune it once or twice a year. However again the grey green fern like foliage and spikes of mildly fragrant pink pea makes them worth the effort. 3a) Pultenaea daphnoides would look great combined with Indigofera. It also has grey-green leaves and yellow pea flowers. 4) Hymenanthera dentata or tree violet. These are prickly and make a great haven for birds if planted in thickets. They can be hedged and the masses of inconspicuous bell shaped flowers have a strong fragrance resembling English Violets. 5) Allocasurina or Sheoaks. Many of these resemble Pine Trees and the shed 'needles' have the same weed suppressing effect as real pine needles. 6) Massed plantings of one of the Austrostipas or spear grasses would be ideal for such a dry slope, e.g. Austrostipa scabra would look particularly attractive. 7) Lomandra sp would almost certainly do well also. 8) The above two could be interspersed with Wahlenbergia sp or Bluebells, Dianellas or Flax Lilies. |
RE: Native groundcover for hard clay soil
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| Thanks for all the responses. I will make a list of these plants, do some reading and visit the local nursery. I'm also wondering what if anything I need to do by way of soil preparation. The slope of the bank is quite steep, so a rotary hoe is out of the question I think. The clay is also very hard, almost as hard as the sandstone underneath. I thought of getting a back hoe in and having him dig it up a bit with the teeth on his bucket but I'm a concerned about erosion if I loosen it too much. Another thought was to cut some terraces into it and then maybe dump some garden soil and mulch in. Even better would be if I can just leave it as is and let whatever I plant go for it. Any thoughts on that? The bank is about 20 metres long, 1.5 high and slopes at about 35 degrees. |
RE: Native groundcover for hard clay soil
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| Hello Silent C ......................................................................................................................................................................................... You are right to be concerned about erosion given the slope is 35 degrees. .......................................................................................................................................................................................... How much catchment area do you have leading to the slope (What is the area of land from which water will flow onto the slope?) ................................................................................................................................................................................. ........ This will determune how deep stormwater flows over the slope. The deeper the flow, the more erosion you will get. If it is only a few millimetres, you have nothing to worry about. Once it gets to a few centimetres, you will start having problems. If it is deeper than that, you can expect that the clay you dig up will start to be washed away along with any mulch. ................................................................................................................................................................................. .......... If you have a lot of water wanting to flow down the slope, and your plants are not giving you complete coverage, your best bet would be to have a table drain along the top of the slope to divert it away - prevent much from flowing down the slope. The log you envisage having there could help with that. It would be good if you could capture at least some of that water in a dam or tank or on-site detention storage that you could use to trickle feed water over the slope later to irrigate your plants. ................................................................................................................................................................................. ........... Otherwise maybe you could try groundcover plants such as Lomandra. I actually think if you are going to tamper with the surface, add topsoil etc., a hardy grass that can give complete coverage would be the best for preventing erosion in your situation (if you can find one). ................................................................................................................................................................................. ............. Best of luck, Frank. |
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