Thanks for all the ideas and advice. I really don't like the look of raised beds, and don't like the expense/extra heat/evaporation issues either. But maybe they would be something to consider in the areas near the tree roots, and then maybe do in-ground beds in front so we can do both. Fascist_Nation, you have given me a lot to think about. We had/have all the irrigation on a daily timer. So I'm guessing the bed got watered too frequently and not deeply enough. It just doesn't seem like that's possible, but I guess it is what it is. I never actually tested it, and then when I was going to see how long the irrigation needed to be on for it be water all the way down, that's when I discovered the entire bed was tree roots. So I haven't managed to find the answer to that yet, but you can bet I will before I start planting in whatever new beds we end up with. I did add composted manure and peat every year -- is that not enough as far as replenishing nutrients? And I'm a little confused about root depth.... If I do in-ground beds there, I'd need to create a barrier (you recommended concrete) to keep the tree roots out. If I do a concrete slab down to 4 ft and then dig the beds 2 ft deep and line them with landscaping cloth, that will keep the tree roots out? For how long? And how well does that cloth really work? The tree roots I found in the bed were very fine, and at first I thought they were leftovers from my veggies of past seasons. Then I found the mother root and realized the tangled knot that was my garden soil was all tree root. We have landscaping fabric underneath the red rocks all over the yard and we do still get weeds coming through it, so I have a hard time believing that the mesquite roots won't penetrate that. (Although I know the concrete will buy us some time.) Wouldn't the tree roots just grow down and then under the concrete and come back up for water in the garden bed? The drainage pebbles are relatively useless right now (they were just for decoration, apparently -- previous owners put that in) but we are planning to redirect the gutters and drainage to the beds.

Hi there, You just described one of my hillsides here in the sf bay area, right down to the old Montery Pine trees and horrible packed clay soil underneath that few things will grow in, and a previous owner who actually thought ICE PLANT would survive on a full-western exposure sloped hill. So we have a couple patches of this ice plant that clings to the hill, blooms a couple weeks a year, and the rest of it annual dry grasses (read: weeds) that either get weed whacked or pulled by hand in the spring after the risk of a mudslide is past. (Our hill isn't that big so hand weeding isn't impossible.) We just repaired the retaining wall for this hill, which means our next project will be to finally plant something there to keep the soil from eroding that won't need to get whacked each spring. Our landscaper recommended 2 plants: manzanita creeper, and a low-creeping ceanothus, I think it's called Carmel something. I think both are drought tolerant and natives. And low to the ground. Another thing that grows well on our hill but seems to do better when it has partial shade is vinca minor. It grows really well in moderately shaded areas. It's also deer proof. And finally, one thing that grows well here, even right below the pine tree right under where all the pine needles fall, is juniper. It's not as pretty, but it sure as heck holds the hill. Have you gone to your local independent nursery? Tell them what you're working with in terms of your slope and soil and that you need a good ground cover... they'll steer you to something(s) that will grow well in your own little microclimate. Take advantage of their expertise, and then once you have the names of the plants you want you can start sourcing them out at the best prices. Good luck, -kristi

List of plants for Moonlight gardens Thanks to GCorman for compiling this list and other members of our forum for their contributions. If you can't make a nice garden out of this lot, you ain't trying very hard! Night bloomers Cereus spp. Datura wrightii "Sacred datura", "Jimson weed" Echinopsis spp. Hesperaloe nocturna Moraea iridoides Fortnight lily Oenothera caespitosa "Tufted evening primrose" Peniocereus greggii "Queen of the night" White/pale blue flowered perennials Asclepias linaria "Pineleaf milkweed" Bauhinia lunarioides (congesta) "Anacacho orchid tree" Convolvulus cneorum "Bush morning glory" Cordia boissieri "Texas olive" Cordia parvifolia "Little leaf cordia" Gaura lindheimeri "Gaura" Jasminum sambac "Arabian jasmine" Lantana montevidensis (white) Lonicera japonica v. halliana "Japanese honeysuckle" Moraea iridoides Fortnight lily Plumbago auriculata Plumbago scandens "Plumbago" Ruellia brittoniana w/white flowers Trachelospermum jasminioides "Star jasmine" Zephyranthes candida Zinnia acerosa "Desert zinnia" Gray foliage plants Acacia aneura "Mulga" Acacia cultriformis Artemisia ludoviciana "Western mugwort" Asclepias subulata "Desert milkweed" Atriplex canescens "Fourwing saltbush" Atriplex hymenelytra "Desert holly" Atriplex lentiformis "Quail brush" Atriplex nummularia "Old man saltbush" Bahia absinthifolia "Bahia" Baileya multiradiata "Desert marigold" Brahea armata "Blue hesper palm" Buddleia marrubifolia "Wooly butterfly bush" Cassia artemisioides "Desert cassia" Convolvulus cneorum "Bush morning glory" Cupressus arizonica "Arizona cypress" "Sabino" Dalea greggii "Trailing indigo bush" Dalea pulchra "Bush dalea" Eremophila cv. Valentine "Emu bush" Euphorbia rigida "Gopher weed" Gazania rigens v. leucolaena "Trailing gazania" Hyptis emoryi "Desert lavender" Lavandula species "Lavender" Leucophyllum pruinosum "Fragrant rain sage" Olea europea cv. Swan Hill "Swan Hill olive" Pedilanthus macrocarpus "Slipper plant" Perovskia atriplicifolia "Russian sage" Psorothamnus spinosus "Smoke bush" Salvia clevelandii "Cleveland sage" Santolina chamaecyparissus "Lavender cotton" Simmondsia chinensis "Jojoba" Sophora secundiflora "Texas mountain laurel" (Silver Peso) Teucrium fruticans "Bush germander" Yucca rigida "Blue yucca" White barked trees Acacia willardiana "Palo blanco" Eucalyptus erythronema "Red-flowered mallee" Eucalyptus papuana (aparrerinja) "Ghost gum" Accent plants for lighting and shadow effects Cereus peruvianus (and v. Monstrosus) Cleistocactus spp. Dasylirion wheeleri "Desert spoon" Nolina microcarpa "Beargrass" Oreocereus spp. "Old man of the Andes" Pedilanthus macrocarpus "Slipper plant" Yucca elata "Soaptree yucca" Yucca rigida "Blue yucca" White/pale blue flowered annuals Antirrhinum varieties "Snapdragon" Cyclamen varieties "Cyclamen" Lobularia varieties "Sweet alyssum" Matthiola varieties "Stock" Papaver nudicaule "Iceland poppy" Petunia varieties "Petunia" Viola varieties "Viola, Violet, Pansy" I've thought of some more - I might add Agave spp. and Palo brea to your accent plants. Does the Abutilon palmerii have gray enough foliage to make the list? I guess it's still pretty green... ? How about Asclepias subulata for accent or gray? And Artemisia x Powis castle - Ok, I know how everyone feels about oleander but I inherited a hedge of petite whites and right now they are beautiful day and night. One to add to your list. Maireana sedifolia or Pearl Bluebush. It's native to Australia and has the most interesting silver/blue foliage. The leaves are about 1/2 inch long and almost succulent-looking and are covered with very short hairs, making it look soft. I had two of these plants at my last house where they received full sun till about 4pm. The plant has a sprawling growth habit to about 4 feet wide and three feet tall. The oldest plant, which was three years in the ground, flowered the spring before I moved. It had tiny inconspicuous tan flowers. Now that I'm in another home, I've planted one on a western exposure about four feet from a block wall.

I agree. Drip is the way to go. I would irrigate the densely planted areas with pressure compensating dripline (Netafim Techline CV). I would use Spray Stakes for the plants that are widely spaced. Use multiple Spray Stakes for plants with large root systems (Netafim Pressure Compensating Spray Stakes) . These products are readily available online. To prevent drainage at the lowest emitter in the case of substantial elevation difference, run each elevation on its own zone, or feed from the bottom and install inline check valves between elevation changes.