I've read here about the idea of combining vines and plants for a longer (if not year- round display).

Could any of you plant experts recommend a combination of climbing and draping potted plants that could be changed out from season to season? When not in bloom, they could be properly supported and maintained elsewhere, and I suppose repotted if the roots grow too large.

Thank you in advance for your thoughts.

You live in such a mild climate zone, that selecting a plant that could be tall and/or vining and look good year round is really not an issue. If you want to plant in pots behind that wall rather than directly in soil, I would recommend that you have such pots hooked up to automatic drip irrigation, and that the pots should be at least 25 inch diameter by 19 inches tall(a fairly standard pot dimension) to support the size of plants to screen that blank wall.

Vines/Espaliers that look good year round in coastal southern California might include things like Coprosma repens with glossy green foliage or one of the colorful foliagecultivars of Coprosma repens such as 'Evening Glow', Grewia occidentalis for deep green fine textured foliage and flat growing habit with showy purple flowers year round, Calliandra tweedii if it faces south or west for showy red flowers, and can easily be trained as an espalier. Trailers to plant in pots above the wall should probably also be picked with drought tolerance in mind, and/or also hooked up to automatic drip irrigation. Easy care trailer for sun might include things like prostrate rosemary, Asparagus densiflorus sprengeri compacta, Convolvulus sabatianus, Juniperus conferta, Pelargonium peltatum. Succulents that trail such as Senecio mandraliscae or Oscularia deltoides, and upright succulents with colorful foliage such as Aeonium arboreum 'Zwartkop' or extra long blooming Aloes such as Aloe 'Johnson's Hybrid', and things like Anigozanthus flavidus cultivars would also thrive in full sun.

If you are going to have plants that get big enough to effectively screen the blank wall, and not have them planted in soil, I would suggest that you size the container at 15 gallon or larger, which makes them a bit bulky to move, but are large enough that they roots don't dry out so quickly. Again, automatic drip irrigation would make a huge difference in plant appearance and growth. You may not even have room behind your brick planter wall to squeeze in a 5 gallon sized container, which limits the size/height of plants that will do well in containers.

Some really fast growing plants that would also work for you might include things like Asparagus retrofractus, Psoralea pinnata, Cussonia paniculata, Acacia species such as A. covenyi, cultriformis, iteaphylla or merinthophora, Melaleuca incana.

Some obvious vine choices for full sun would of course include Bougainvillea or Mandevilla 'Sun Parasol Giant Crimson', along with others such as Dalechampia dioscoreifolia, Passiflora 'Lavender Lady', Petrea volubilis, Podranea ricasoliana, Pandorea jasminoides 'Rosea', Stigmaphyllum ciliatum, Thunbergia alata or T. gregorii, and Thenardia floribunda.

The problem I see with this idea is the limit on the size of the pots. It is hard to get plants to look really good in small amounts of soil, since they do not have enough room for their roots and the soil dries out. If you put in really big pots you will have difficulty rotating them in and out. Lifting a wine-barrel sized container full of dirt and a six foot tall plant out of a planter sounds like a lot of work to me. It would also be hard to disguise the top of the pots.

My first choice in your situation would be to tar the heck out of the inside of that planter and put drain holes in the front and to plant directly into dirt.

But if you really want to go with the pot idea, you should make sure the pots drain out the front of the planter and that water does not build up against the garage. Pyracantha would be beautiful espaliered against the wall. It gets blooms in the spring and red berries in the winter. Another option would be annual morning glories for the fall. Plant them in late spring, move them into the planter for late summer and fall, then toss them on the compost heap. Roses are another possibility: either tree roses or climbing roses on a trellis.

As far as plants on the roof- you would have to put down a rubber liner and channel the runoff so that it did not wreck your roof. It would probably be wiser to hang a window planter box off of the side of the building at the proper height.
Good candidates for this are Sprenger asparagus, ivies, and iceplants. These plants can take the heat of a roof and survive.
Good luck with your project.
Renee

I did end up waterproofing the planter and filling it with soil. For the time being, we put in low plants and some draping over the edge of the planter. But it does still need something against the wall to give it a better scale. After considering boston ivy for the changing colors, I am now looking for a nice trellis system instead, to support some of the vines you have mentioned.

Just thought you might be interested: I saw a living wall installation at the SF Garden Show. It was very impressive. The plants were grown in canvas "pockets" which were lined up, vertically and horizontally, and hung on a wall, and you couldn't even see the pockets without close inspection. Each pocket held about 3 or 5 gallons of soil, and were fed by a drip system. These pockets could be switched out, taken to a potting shed, or a less conspicuous location when out of season. Wish I could remember the name of the business that made and sold them, but if you google "Living Wall" you'll find numerous such products and installations.

We have a 10' Camellia bush growing in a planter about 1.5' high and deep, along the north side of my house. the trunk is about 4" diameter. It's been there since before I came, looks great. I don't know if the planter has a bottom in it or not. But I wish the camellia had been espaliered when it was young, to keep it against the wall.