A drip should work fine, a few suggestions for drought tolerant vines include hardenbergia, bougainvillea or cat's claw. Other than the big flowering time in the late winter/early spring the hardenbergia will give you the least litter and look nice all year. It will give tons of coverage if you start it on a trellis.

Thanks for your input. Any thoughts on Creeping Fig (potentially invasive I know--it will be on a metal grid trellis, not on a wall, far from any wood structures) or Star Jasmine? Ideally I'd like no flowers or small flowers.

OK, so this plan yielded mixed results. After fully ammending soil I planted cape honeysuckle on a sturdy trellis on one wall (faces south), star jasmine on a sturdy trellis on the other wall (faces north) a bottle brush tree, and three Meyer Lemons that I planned to maintain as a hedge. All are doing fine on a drip system with half day sun except the lemons. Within a couple of months of planting three small plants last October there was heavy leaf drop and dried out looking leaves. Increased the water, waited another 2 months but no real improvement. They looked terrible and I removed them. Planted three new lemons in February, larger plants with about a 1.5-2 foot canopy (hoped that they would be more hardy). All on a drip system that runs 3X a week for about an hour and half, with two 1.0 GPH drip emitters over the rootballs. Fertilized with slow release for citrus. Again, the trees look terrible after 4 months. I understand drip is not ideal for citrus, but it seems like the watering should have been fairly on target (not too much or too little). Maybe not enough sun? I'm surprised that though conditions are not ideal that I have had two failures.

Any suggestions for other plants that can work as screening plants in a narrow, part sun space? Ideally evergreen, not too messy, at least 7-10 feet tall to obscure a carport structure directly behind the patio.

Thanks for any suggestions or comments.

I don't know why your lemons won't grow. Anytime I've had problems with plants not thriving I've found that the roots were circling, which is a slow death for the plant. It will survive but not thrive and inevitably it will die. Did you find circling roots with your first lemons?

A suggestion is fast growing Yellow Bells (Tecoma Stans), the yellow is more hardy and the orange one is prettier:
http://www.wildflower.org/plants/result.php?id_plant=TEST

Another suggestion is Heavenly Bamboo (Nandina Domestica), a beautiful easy care bush that you can let grow naturally or trim as hedges. It is beautiful all year round and very forgiving with water. I have three of them, just love them. The one in the photo (left side) is 7 years old and only 4 ft tall, it's a slow grower.

Here is a link that might be useful: Heavenly Bamboo

Here's another plant that might be more what you're looking for.

DODONAEA viscosa (Hopbush, Hopseed bush).

With little water it will grow to 6-8 ft, with more water it will quickly grow to 15 feet. Space them 6-8 feet apart and prune as hedge or left unrpuned it becomes a big informal screen. Can even be trained to be a tree. Zones 7-9 or 12-24. The most popular variety is 'Purpurea', with rich bronzy green leaves. Willowlike leaves to 4 inches long. Drought resistant when established but can also take ample water.

Good luck!

Thanks for the suggestions. Heavenly Bamboo won't get tall enough I'm afraid unless their growth is different in the SW. Here in the PNW they are widely planted but the height never exceeds about 5 feet.

One additional challenge to this space is the fact that it is narrow. I read that hopbush can get 10-12 wide. I imagine I could shear it but I'm not sure how attractive this would be.

Ideally the plant would get tall but not more than 4-5 wide. The plan with the (failed) citrus was to grow it as a hedge.

"Planted three new lemons in February, larger plants with about a 1.5-2 foot canopy. All on a drip system that runs 3X a week for about an hour and half, with two 1.0 GPH drip emitters over the rootballs."

According to this scehdule you are delivering about 3 gallons of water each time your system runs. If your trees were in 15 gallon containers you're going to need about 2 gallons of water just to moisten the rootball, not including any surrounding soil. I'd recommend either adding more emitters or changing the emitters you have to 2 gph or even 4 gph.

Citrus need to be watered generously and then allow the soil to dry just a bit before applying more water. You can add a layer of mulch on top of the soil to slow evaporation and keep the soil cooler. Just don't pile the mulch against the trunk.

U of A Citrus experts don't recommend fertilizing the first year.

Wrap the trunks loosely with burlap, cardboard or tree wrap to prevent sunburn.

Here is a link that might be useful: Citrus irrigation and more

Thanks for the information. I think the plants were 10 gal but I get your point. I thought the watering amount/schedule was fairly on the ball from what I researched but it is hard to make adjustments when I don't live in AZ full time and can't monitor the health of the plants except on visits... I'm tempted to try again just because I love the trees and fruit. On the other hand maybe they're too tricky given my circumstances and I should try something else. Another thought was a row of very narrow columnular juniper like Skyrocket. Not sure if this type is even available in AZ but maybe there is something similar that is better adapted? The bottle brush is doing well and I've also thought of just adding another. The courtyard is very small so I don't want too may plant types or it will look busy and crowded.

You might consider thevetia -

We have a long hedge of these and they can get bushy but are easy to keep trimmed - no thorns. I will plant 2 or 3 this fall to shade the garden area.

Here is a link that might be useful: Thevtia