Question
My house is almost 20 years old and set below street level - there is a
descending driveway to parking area.  the street side of driveway is about 10
ft high - street to asphalt drive.  There is no specific retaining wall. Nor  can I
see where to put on.  The rest of the drive "wall" is  planted.  The rocks have
since sunk into the ground and are overrun with weeds. We think there is
even more erosion as the asphalt drive has cracks and developed a sink hole.  
The two other slopes on the property have a 5ft flat -area before sloping but
these seem to be diminishing as well. There are signs that the ledge is being
pulled down the hill.  We are afraid to replace the current shrubs because we
think these shrubs are all that holds current soil from falling further down the
hill.  These two types of areas are our biggest concerns and we are not sure
what to do? We need to know immediate remedies and long term solutions.
Cost is an issue, so whatever we can do ourselves is our first preference but I
suspect this is going to be a big soil replenishment project.  Your attention
and response is greatly appreciated.

Answer
Hi Lisa

It sounds to me that you do have a serious erosion problem here and the cracks in the asphalt are a clear indication of this.

I think that it would be wrong to remove the shrubs as these probably really are the only things holding together the slope. Therefore, some drastic action maybe needed here and that means either terracing the slope in stages or building some meaty dry-stone walls.

I think that I would suggest hiring a mini excavator and terracing the slope into maybe 3 terraces. These and the drive itself can then be haunched up with small dry-stone walls. These walls could then be planted with plants like Rosmarinus officinalis 'Prostratus',sedum rupestre and sedum acre to make an attractive feature.

This can all be done by you guys with the minimum of advice from a local builder.

Good luck!

Jonathan www.ecologicagardens.com