I am one of those living on a protected canyon in San Diego, Serra Mesa area, and we had a big mudslide. I would like to plant some thing to curtail the mud slides and something that would be natural to the area. It is a steep slope and is a fire danger, little water available. Would something like this be good
Baccharis pilularis pilularis Pigeon Point

along with some oaks and a few Rhus ovata there's not much you can do

I am working with Caltrans on an R&D project to stabilize a slope on HW46. The slope is about 2/1 and runs 180 feet from toe to top. The soil is an Obispo series. Three past attempts to stabilize the slope with hydroseeding have failed. I presented a new technique using compost as the main ingredient. Once I stabilize the slope it will be again hydroseeded. Could you help me with the selection of the grasses and other plants to be included in the hydroseeding. Do you have these seeds?

sorry, I do not believe seeding or compost will work
and, we do not sell seeds

I've just finished up the building plans for a house on the property and I got thrown for a loop when I saw the specs for erosion control on the grading plan (which unfortunately I didn't see before they got filed with the County). I'm waiting for a call back from my architect, but I thought I should try to arm myself ahead of time. The erosion control plan includes hydroseeding with a mixture of seeds that is primarily grasses (annual rye, orchard grass, and sierra oats), with a tiny percentage of wildflowers thrown in for sport. I know how strongly you feel against using grasses for erosion control, but I'm wondering if you know if this is a County requirement.

That is, I doubt if my architect made up this mixture on his own and it looks like it might be boiler-plate. Am I out of luck or do you think I can specify my own seeding mixture and get it through the permitting process at SLO?

I've been seeding with California natives for four years now (many thanks to you and the reference to a bulk seed company) and the thought of introducing more grass seed really bothers me, but the overall amount that will have to be used around the building site may be too small to get up in arms about.

Do you have any advise?

we've fought their stupid policy for years, but dispite every study ever undertaken proving the contary, the county engineers think they know best. you can, but it's a hell of a job to teach an idiot anything(never mind a bunch of idiots), if you can use your wildflower mix with some Stipa lepida for the grass, that would be good.
A Farm supply or many nurseriers sell weed killers that only kill the grass, gives me a terrible headache, and you have to do it as soon as they germinate, and repeat it the second year, but sometimes it's the only way you can build your house...

Do you have any suggestions for plants that can help to slow beach erosion> I own beach property in Northern california and
the property at the coast is kind of slowly melting away. I heard that planting really helps slow the erosion.

Thank you!

we've found weed control dramatically helps erosion
Look at erigeron glaucus
Erophyllum stachifolium
Baccharis piliularis 'pigeon point'
Ceanothus 'heart's desire'
Eriogonum parvifolium
Elymnus condensatus