I'm not sure what you read that made you so pesimistic. I will tell you that I certainly felt that way to start with. I live in the NC piedmont which stands for a deep vein of red heavy clay soil. White clay is even worse as it indicates that air can't get into the small particles and rust the iron to red. However it is plenty hard and slimy clay like when wet. We have the largest hand thrown pottery community here. Thirty miles south, the soil turns to sand and the interface is the brick capital of the country! I doesn't appear that anything except grass will grow in this soil. However, if ammended heavily with bulk, it does wonderfully as it holds water and nutrients extremely well. We are in the country. I found a cattleman who has cow manure/bedding piled up and mixed after being mucked out of the barns. I bought a dump truck load (I actually bought two and moved it multiple places later) and had a third to a half of it dumped in my ~25' x 35' garden and tilled it in. That could have been between 6 to 10 cu yds of black composted manure. That changed the texture of the soil and it is still there after 6+ years. Gas was much cheaper then and it cost me $60 for delivery and $50 for the manure. Would be much more now for delivery.

First of all a little background. I am a graduate of Cal poly Pomona, I am a licensed irrigator in California and Texas. I also own a tree farm in Texas . White Hall Trees. In texas we do not have gray clay we have black clay that is at least as bad as what we had as a kid in California( I grew up in Orange County) Now with that said. The problem that everyone seems to have is the same. You claim you cant get fruit trees to grow in clay. Being a Civil Engineer, Landscape contractor and LI for 30 years I have some basic recommendations. First Clay is an excellent way to hold water ! and fruit trees need water! But not so much as to be wet all the time. First raise the tree about 3" above existing grade. When planting dig the hole twice as big around as the pot and 3 inches shallower than the pot . When back filling around the pot use a 3/4 to 1/4 ratio of good composted material to the clay and Float the tree back in. Simply put add water to the soil to get out air. Then ad 3" of good hardwood mulch around the tree. The biggest problem that you have is water so call Ewing Irrigation or John Deere landscapes and get some Rainbird .26 Drip tubing on 12" centers and drip the trees! If you circle the tree with lets say 6 drip emitters and water for 10 minutes you water .26 gal of water. Lets say the tree needs 3 Gal of water per week in one hour you will water 1.56 gal of water. So water 2 hours per week ! You may need to water Tuesday and Friday for 1 hour each day and check the tree hole with a moisture probe you can buy at one of the local Home depots for about $ 10.00 The biggest deal is don't guess ! Test and check ! Make sure. If you need more than 3 gal of water per week they have drip tube in .26, .4,.6, and .9 Netafim, Rainbird, Hunter, and Landscape products all make drip tube ! Do the calculations and if you are unsure call an irrigation professional they can help. The guys at Ewing can also help if you ask and by the way if you bring donuts to them they even get nicer !!!!!!!!!!!! Try It !

If you can't reasonably dig down, what about building up? What would you think of putting in a lasagna bed (kind of a big wide sheet of compost) and planting into the compost? the idea is that you let the compost hold moisture against the clay and you let whatever lives in the soil do the work of penetrating into the clay. You might help it along by planting a first year crop of Daikon radishes. You plant them not so much because you love radishes, but because they have a very persistant attitude about poking their root down into the soil. This leave lots of radish root sized holes into the clay the next year. After this first year of prep work you go full strength with natives and allow them to take over. I should note that I am not familiar with zone 9. Up here in yankeeland I would expect the above to be resonably reliable.

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.