Can part of a vine climbs and other part crawl/spread? I bought a Jasmine Star of Toscane. http://davesgarden.com/guides/pf/go/188353/ and hoping it can cover the retaining wall, while sending roots out for erosion control.
Vines will climb if they have something to climb, and if not then they'll sprawl along the ground. If you want it to do both you may need to help it to get started in the directions you want it to go. Given the size of your area though you may have better luck if you buy more than one plant--have a couple that you train up the wall and a couple that you plant on the ground in the middle there to sprawl along the ground.
Also probably worth mentioning that this vine will not climb the retaining wall on its own--it's not like ivy that has little sticky things that can attach to solid surfaces, it will need trellis, wires, or something like that in order to climb.
Thanks! I read some jasmines like Tricolor and Gold Brocade don't flower unless it's grown as a climber. I am concerned that this applies to all jasmines, so I am more inclined to let this one grow as a climber too.
They'll flower even if they're sprawling on the ground, assuming other conditions are right (enough sun, etc). Sometimes variegated cultivars don't bloom as freely as the plain green ones (not sure if that's the case with the two you mentioned) but it has nothing to do with whether it's climbing or not. Only reason one of them might bloom better while climbing is if it's too shady on the ground and climbing enables it to get sufficient sunlight.