First, the back story: My sister's house in San Juan Capistrano is on top of a very steep slope of expansive clay soil where there has been some erosion. I don't mean topsoil washing away. I mean when there is a heavy rain, large chunks of the hill may slide down. She hasn't had any severe problems yet, but neighboring houses along the same slope have had some major issues. Many years ago, I had a property where after we did some grading, the engineer recommended that I should plant junipers on the slope since they have deep roots of steel that that would eventually form a web locking the topsoil into place. 

 

Fig trees grow a lot faster than junipers and they seem to have pretty substantial roots. Also, my sister is paranoid about planting anything on her slope because she is afraid to water it, causing more erosion. Fig trees don't need much water and once established, could probably survive just on the fog that rolls off the ocean in the morning. Most importantly, I've got so many duplicates of the more common varieties and they are still multiplying. Over the next couple years, I could probably have her slope covered in second rate fig trees. Does anyone know if fig trees would be suitable for this purpose? I don't want to go through all the trouble planting them unless I can find some evidence to support my theory. Any geological engineer figsters in here?