Ask Mr. Smarty Plants

Perhaps the very fact that you have already tried a number of vines is an indicator that you need to change your expectations and your plans.We believe that the problem is that the water falling constantly on the soil is drowning your roots. It's likely you have clay soil, which doesn't drain well at all, and with no compost or other organic material in it, the water is just going to sit there. There are two routes you can take: one, put in plants that can actually grow in watery soil. These won't be vines but they will be attractive and structural. Two, build a raised bed beneath the trellis, fill it with rich composted soil and plant your chosen vines in that. On each of our lists of suggested plants, follow the plant link to the page on that plant to learn what kind of soil it needs, how big it will get, whether it is evergreen, and when (or if) it blooms. 

First, let's look at the possibility of building a raised bed. Here is one article on the construction of such a bed from Popular Mechanics. Another take on the problem comes from About.com: Organic Gardening, Raised  Bed Gardens. 

We are going to continue on this line and look at vines native to Southern California, Orange County, and see what is available. These may be vines you have already started and they have died. Hopefully, once you have given them better dirt to live in, they will do well. Okay, now we remember. Once before, recently, we searched for a vine for Southern California, and it's pretty slim pickings. Most of the vines are more woodland plants, and are found north of you and on into Oregon and Washington State. However, we scored three:

Vines Native to Southern California:

Clematis lasiantha (pipestem clematis)

Lonicera hispidula (pink honeysuckle)

Vitis girdiana (desert wild grape)

Now, moving on to "water plants," we'll see what is native to your area that could manage standing in all that mushy soil all the time. These are all members of the genus Equisetum, are considered grass-like plants, and can be planted in pots submerged in ponds. They don't flower and they are not going to climb your trellis, but it's the best we can do at this point.

Equisetums native to Southern California:

Equisetum arvense (field horsetail)

Equisetum hyemale (scouringrush horsetail)

Equisetum hyemale var. affine (scouringrush horsetail)

Equisetum laevigatum (smooth horsetail)

One last possibility, but you will be abandoning the trellis with vines climbing concept. Again,  build raised beds, and then plant attractive low shrubs and let the fountain water them in their new, well-drained bed.

Background Shrubs for Fountain in Southern California:

Calycanthus occidentalis (western sweetshrub)

Holodiscus discolor (oceanspray)

Mahonia repens (creeping barberry)

Rhododendron occidentale (western azalea)

From our Native Plant Image Gallery:

Clematis lasiantha

Lonicera hispidula

Vitis girdiana

Equisetum arvense

Equisetum hyemale

Equisetum hyemale var. affine

Equisetum laevigatum

Calycanthus occidentalis

Holodiscus discolor

Mahonia repens

Rhododendron occidentale