Lavender will definitely be unhappy in part shade.

How long is the area in shade and is it morning, midday, or afternoon shade?

The tree may also contribute to the problem, many large trees take up enough water during the day to essentially suck the plantings below dry. if its partially moist try Plectranthus (varietys) they will take sun and shade. also try Ruscus and Heleborus.

I'd look for California native grasses that typically grow under oak trees. They'll be adapted to both shade and dry summer soil. Check out the grasses section at baynatives.com for ideas.

I also just noticed this thread: http://forums.gardenweb.com/discussions/2998722/need-suggestions-for-drought-tolerant-shade-loving-plants?n=6

With the drought, the wisest thing to do is to mulch so the area looks neat and cared-for, and wait until fall rains begin (if they do) to try planting anything. With watering restrictions, no one is going to complain about other people's landscapes this summer.

Actually many many succulents do fine and dandy in part shade, because that is where they grow in their native lands.

Some larger succulents like agave do well in shade if she wants accents.

I like both boovb's and Sabine's responses. Will add that pine trees and their needles will create an acidic soil so if you do plant something, make sure it can tolerate that condition.

First, Norfolk Island pine is not a pine tree - that is just the common name for Araucaria heterophylla, a completely different type of conifer.

Also the notion that pines or other conifers and their dropped needles increase soil acidity is a gardening myth. Plant material has no significant impact on soil pH. A soil is acidic if it is derived from acidic base rock and rainfall is a major factor as well. Areas with heavy rainfall tend towards acidic soils - arid areas tend to be more alkaline.

Most of SoCal has a neutral to slightly alkaline soil pH. And this is exacerbated by alkaline irrigation water. You would need tons of pine needles to make even a slight decrease in pH at the soil surface. It would remain unchanged below the soil surface.

Thanks for that lesson gardengal48. I'll stop perpetuating that myth.

If she lives in a frost-free zone, there are tons of South African succulents that will flourish in half-day sun, or dappled shade, if soil is well-drained. There may be some suitable Australian plants too. A visit to the jaw-dropping succulent garden at the Huntington Library in Pasadena (with a camera and a note pad) might provide ideas. Does the spot get morning sun or afternoon sun?

Oh, and suggest she visit her water department's website. A surprising number of southwest water companies/departments post a recommended low-water plant list on their websites.

It's hard to say without seeing the location, but maybe she should check out the Tree of Life native plant nursery in San Juan Capistrano on Ortega Highway. Their website is a good resource as well.

tfswest, I would not trust the water company site info. Our water company had such glaring errors that I wrote them a letter. I never received a reply and they didn't change the page info for many months (at a planned site redesign). A few examples of their errors:

--They recommended a plant I had never heard of and wasn't listed in any plant books for this region, much less seen in any nursery. I looked it up online, and discovered it was a native creek-side woodlands plant from the southeast portion of the United States. It didn't even appear to be sold in eastern US nurseries.

--The wild lilac (ceanothus) recommendation showed a photo of a Syringa vulgaris cultivar/French hybrid lilacs, a completely different and unrelated species. in fact, they aren't even in the same plant family!

--Three other plants listed require regular watering; they were not normally considered drought tolerant by gardeners.

--At least one recommendation was listed on CA's invasive plant list, and the state discourages it being grown in gardens.

--Two would have probably required a mail order purchase, because they are not generally offered through the nurseries and garden centers here. And one of those liked winter chill--not something generally expected to a sufficient degree in south OC.

The two site pages only listed about 16-18 plants total, so there were problems with the majority of their recommendations. I would have given their info an "F" grade.

Agaves and Aloes!! Will grow under most any conditions

Gyr_falcon, that doesn't surprise me at all. Our water district up here in the south bay area had a lot of misinformation also. Listed plants not drought tolerant and left out many common drought tolerant plants. Most of the the research and list compiling is done by unpaid interns, some are hort. students, but a lot are not. Their work is overseen by the director of the project, but she's by pretty overwhelmed by the number of people who are applying, and understaffed. I wish these districts would staff the project with the appropriate number of employees, right now it's really bad.