Podocarpus and pittosporum silver sheen are both used for privacy screens and grow well in Southern California.

I once saw a back yard similar to yours with the same view for the neighbors. These folks planted a row of a variety of bigger/tall trees very near the fence/wall. As the trees grew they trimmed them up to the top of the fenceline so the neighbors' view was limited by the full branches, but there was no bulk down below to take up precious back yard space. This also provided shade for their own back yard.

Do you need just the apartment's window(s) screened, or do you want to screen the buildings themselves? In other words, do you want a tall hedge or only spot-screening?

In what direction does the fence run, North->South or East->West?

What style is your house? You want a large plant to not look out of place.

Do you want a very dense screen, or an airy one?

Must it be very clean, or is leaf/flower litter not an issue?

Avoid all Ficus because of your retaining wall. Avoid anything too large, again because of your wall.

Thank you everyone for your suggestions.

To: hoovb

Your questions really are great and I didn't think about them until you asked, so thank you. I'm attaching a pic of what I'd like. I'd like airy to screen my view of the apartment's roof. I'd like a dense screen from on the 2nd floor apartment unit's window and door entry.

I believe the fence is located SW. See my pic.

The style of my house: 1926 bungalow.
Please excuse my embarrassing fence, ugly grass and house siding. My husband and I are restoring the inside first, but thought we need to get a jump on the green screening to allow whatever we plant to grow.

I am open to very clean or leaf/flower litter.

I like Duranta, especially the green and white variegated one, but they are sensitive to frost. I also like Springtime Viburnum, Texas Privet, and the smaller varieties of podocarpus, like Icee Blue. Bottle brush is really pretty and makes a good screen, and it attracts Orioles. I like the Pittosporum Silver Sheen, but mine does not like our hot August weather and loses its leaves when temps get into the triple digits.

Another thing I really love and would do if I had the space is three Italian Cypresses of different types and heights planted in a triangle, The LA Arboretum has three of them in a circle planter with other shrubs and it looks stunning. I love the bright chartreuse ones mixed with the blue colored ones. You may not have enough space for that either though.

My house is located in Los Angeles, SouthEast San Fernando Valley.

how about Osmanthus frangans? it makes a nice hedge. and silver sheen pittosporum is great for airy.

Do not apologize for your bungalow! They are wonderful. It's great you are taking up the challenge of restoring one.

'Silver Sheen' is a gorgeous airy tree, but it struggles away from the coast. SFV I think it might be too hot for it, but look around your neighborhood and see if any are growing and thriving nearby. If you see some that have been there more than five years and look great, a definite option.

For the dense area I would look at Syzygium paniculatum, which for decades was the ideal narrow screening plant for Southern California; this all changed when a psyllid arrived that ruins the foliage, HOWEVER, the state released a psyllid-predator that seems to be keeping the psyllid under decent control; you get some damaged foliage, but not enough to make the plant look particularly bad or kill it off. Let them grow to the height of your neighboring apt building or a few feet shorter, then top and shear as a hedge. Quite drought-tolerant once established and do not plant too close to the fence, 4 or 5' apart and at least 4' from your fence. If you keep them topped and trimmed, they will be happy and well-behaved for decades to come. The Syzygium you see would be historical to the youth and middle age of that bungalow.

A another really classic choice would be Hollywood Juniper, Juniperus chinensis 'Torulosa', which was so popular 1920-1970 it got named after Hollywood.

Another historical choice for the dense portion, if you can sacrifice some space, would be citrus trees, which are also beautiful ornamental trees--a lot of people forget that, not to mention the out-of-this-world fragrance of the blossoms. They made nice screens and do not get too tall (avoid grapefruit--they can get huge, unless you get one on dwarfing rootstock). Choose a citrus you are going to enjoy eating, not an oddity with fruit you don't know what to do with.

For the airy, you have a lot more choice. Look at some small, choice palms (NOT trashy, reseeding-everywhere-pest Washingtonias, which end up costing a fortune to trim and are habitat for rat infestations, avoid!). For example the Mexican blue palm, Brahea armata. Some of the smaller Crape Myrtles are lovely. See "patio trees" section in the Sunset Western Garden Book for more. Your lot is probably too small for a larger tree and a large tree with ruin the look of your bungalow by overwhelming it proportionally. Medium shrubs (20-30') can make excellent shade and screen for bungalow properties.

Hoovb, it sounds like the OP is more in like Burbank than Moorpark. The silver sheens will do ok there with water. But your point is a good one.

Brahea armata, while stunning, grows really slowly and not all that tall plus the bloom spikes might be too wide for the side. Toyon grows fast, has white blossoms and red berries birds love, can be limbed up, is native and is now the official shrub of Los Angeles. It comes in a golden berried form, David Gold. It is drought tolerant and it will take summer watering.