If you live in New York as suggested in your name, you might want to search on cliffandjoann. They built a stunningly beautiful pond and have explained the details. They say that some of their plants are in pots. I use impatiens and am under the impression that they will grow without much actual soil. It is certainly true for water cress (from the grocery store) anchored directly in flowing water. For something larger, sweet flag will certainly work. You can also use vines or other plants growing beside or near the area. You can also add logs or other natural materials for interest and coverage.

Landscape roses are considered groundcover roses. They are low growing shrub roses (typically not exceeding 3') that spread much wider than they grow tall. Drift, Knock Out, Flower Carpet are all readily available landscape groundcover-type roses. It is not a defined category, but the roses are bred specifically for these attributes. They also tend to be very free flowering and low maintenance compared to other rose types. The issue with most groundcover clematis is that they behave exactly as do their vining cousins....except they don't vine :-) So for the most part, they are not tidy little clumping things but large rambling plants that can easily grow several meters a season. Combining the two - the wide, sprawling landscape roses and the long, rambling clematis - may not be as simple as it sounds without very careful cultivar selections.

We put plastic over our ground cover to try and kill it and then mulch on top. Don't want to use pesticides because we want to replant in the garden.... Well the ground cover survived and grew through the plastic. It will not die. I rip it alk out every year and it comes back no matter what. It's a fight that never ends. It chokes out my other plants. This year I'm planning on launching a full attack.

There's a lot of microclimates in the SFBA, and the CA Gardening forum is pretty heavily weighted towards SoCA. But specific questions for NorCA plants usually get a fair # of answers - but again, you need to be more specific about where you are. In SF, for example, the soil is sandy and water runs right through it. In the EBay where I live, the soil is adobe clay. Half of the EBay is still in the fog belt, while anything east of the hills resembles SoCA in climate. If you are anywhere near state/county parks or swaths of grasslands, be very very careful about what you plant, if there is any chance of invasiveness. "Iceplant", generally meaning Carpobrotus edulis, is listed as invasive, while Delosperma cooperi, which looks very similar, is not. I was just reading the threads on kurapia (Lippia nodiflora) and it looked like this plant needs summer watering. It is not a true drought resistant plant. If you are only planting a very small lawn, once-a-week watering sounds fine. But if you've got a third of an acre, that's quite different, LOL. Personally, we got rid of the lawn decades ago. No kids and no reason to keep it. I wanted a localized version of a cottage garden, adapted into multiple beds separated by the usual concrete walkways, driveway, patio, etc. Totals about 2300 sq. ft. garden. Not only do we have flowers year round, I only water with soaker hoses every 4-6 weeks, depending on how much fog we get. I cannot conceive of watering every week - the potential EBMUD bill staggers my imagination ;)) I have been searching for the ideal groundcover for years. The two best drought-resistant ones I found for my area are aptenia and groundcover lantana (there's a shrub version of lantana; you don't want that). Both are full sun, however. Both have their negatives. Aptenia IS invasive, so I plant it only where it is confined by concrete. It does appreciate a little bit of summer water, especially during those extended heat spells that seem to be happening more often these days. Lantana once established will survive without any summer water at all. Zip, none, nada. However, it mounds upwards (similar to ivy) as well as outwards, so it rewards being cut back/whacked down periodically, which can make it go through an unattractive stage, depending how drastic you had to be. The white lantana is extraordinarily vigorous. I once let one plant trail down a concrete wall and across our driveway just to see if it would stop growing at some point. I finally chopped it back after it reached 17 feet without any indication it was slowing down! Width was fairly even at about 2' across all the length. Lantana is supposedly also deer resistant; it has a rather unusual smell when crushed. Aptenia is greatly appreciated by our local bees, who love the flowers. Anyway, hope my experience helps the OP a bit. Go to a good nursery and see if you can talk to someone, too - I've always found it a good way to get solid advice. Golden Nursery/San Mateo and East Bay Nursery/Berkeley are the best sources for both advice and plants, IMHO. Cocoa hull mulch is the premium mulch - breaks down (relatively) quickly compared to bark, and really enriches the soil. Thus it is also the most expensive, as well. The chocolate smell is nice but fades rapidly. Remember not to let any mulch pile up around shrub/tree trunks. Cocoa hull mulch, if watered by sprinkler, will develop an unattractive but apparently harmless greyish-white fungus on the surface.