From: jhb@calmasd.prime.com (Jim Bishop)
Newsgroups: rec.gardens
Subject: Re: groundcover for steep hilside w/cement
Date: 7 Nov 92 07:46:40 GMT
Organization: -

In article <1992Nov5.152434.25445@mmm.serc.3m.com>, 
us048503@mmm.serc.3m.com (Art H. Hurst) writes:
>  	My wife went to a local nursery and talked to the resident
> 	landscape expert who when she found out we were putting cement
> 	in the soil said she didn't want to be involved! Even for money!

Cement isn't great, but most of us have it in our yards thanks to the
job most stuccoers do.  I also I assume you aren't mixing the cement
into the soil, just using walls to hold up the hill.  I use broken
concrete to build walls and plant right over and around them with no
problem.  Concrete will make the soil alkaline, but our soils are
already alkaline (as is our water).  

> 	We are in the process of rebuilding the slope. We had ivy on the
> 	slope for 25 years with no problem. It appears that the slope
> 	was never originally compacted properly but with 14 " of rain
> 	per year it was never a problem. Last year we had 32"! 6" alone
> 	the day it failed, and that on top of about 1 week of heavy
> 	rain. Some people have said to use coyote bush, oleander, some
> 	even ivy. 

Coyote bush would work well on a slope, but isn't too attractive.
Also if you mix it with oleander it may be mistaken for freeway
off-ramp. ;-)  However oleander does work well on slopes, but I don't
know how deeply rooted they get.

I wouldn't put it more ivy, but if you've had it in the past you
already know what a pain it can be.

I wouldn't recommend ice plant even though it will stablize some
hills.  Overtime it can get quite heavy and actually lead to bluff
failure with all its weight.

Some natives that might work ceanothus, fremontia, cotoneaster,
California fuschia, or rhus (sumac).

Some low water non-natives (not all are ground covers but they do well
on slopes): New Zealand flax, cistus (rock rose), acacia, correa,
lantana, plumbago (There's a new darker blue out, but I haven't seen
it.), erica, verbena, new zealand tea plant, rosemary, oregano, echium
fastuosum.  All of these will give you that California/Mediterranean
look.

I also like slopes planted with succulents.  I've found that aloes and
agaves send roots out in all directions.  I think they would be great
for erosion control.  The also looked great mixed with rocks or
cactus.  They are very low maintenance.  There are some
spectacular slopes planted with succulents in Southern California.
(The Huntington in Pasadena has one of the best succulent gardens in
the world if you want some great ideas.)  

In the front of Sunset Western Garden Book is a list of plants for
slopes and erosion control that might give you some more ideas.  I'd
definately try to mix it up a little, nothing worse than a hillside
planted in a single species.

>       The city inspector said 'no ivy'. Some say to use a
> 	spray seeder, but my wife has seen two places that did that and
> 	both are totally dead! We are about two weeks from putting
> 	something in. The whole project is in progress right now. 

I believe spray seed consists of annuals and dies when the rain stops.

You are in luck on the timing, this is the best time of year to plant
in Southern California.

Jim